Spinach Herb Pesto

spinach herb pesto

Happy spring everyone! It’s been a flurry of activity here at Casa Scalzitti for the past few weeks. After finally recovering from the miserable virus we caught in Italy, Peter and I sprung into action and tackled our household “To Do” list. The first day of spring may have been a couple of days ago, but here in Houston, we’ve been enjoying beautiful spring weather since the beginning of March and it’s been glorious (North-Easters, please don’t hate me!). The start of spring this year is especially exciting for us because we finally had our front and back yard re-landscaped. Our flower beds were in need of a re-fresh; we added hardscaping in the back yard for improved drainage; and the best part: we had our patio re-modeled and I (finally!) got my raised garden bed. Once the patio re-model was finished, Peter and I wasted no time in buying new outdoor furniture, planters, and a grill to create a comfortable and functional outdoor living space to enjoy together. I also planted vegetables and herbs into my raised garden bed and my plant babies are flourishing with new buds, leaves, flowers, and the first tomatoes. I may have a green thumb after all!

As much as I love the cooler months here in Houston, I’m always happy when spring arrives. I’ve since grown tired of hibernating indoors, wearing sweaters, and heavy winter recipes. Now, with the longer days and warmer weather, I’m ready for lighter fare and the fresh, colorful produce of the season. On a grocery run to Trader Joe’s last week, I came across newly arrived basil. I know…it’s really early in the season for basil, but it was fresh and was packaged in a larger quantity than usual, so I couldn’t pass it up.

While I normally consider myself (mostly) a purist when cooking Italian recipes, I do enjoy sensible variations on the classics, and pesto is one of them. I had a package of baby spinach at home and knew I wanted to make spinach pesto with it, and once I bought the basil, I decided it would make a flavorful addition along with some fresh flat leaf parsley I had on hand. Now that I’ve created this spinach herb pesto, I don’t think I’ll ever go back to making plain spinach pesto ever again.

spinach herb pesto

Whenever I make any kind of pesto sauce, I always eyeball the quantities of garlic, pine nuts, olive oil, and cheese based on the amount of greens I’m using. I know “eyeballing” is hardly accurate (or helpful) if you’re new to making pesto, but there are things to look for as you make the pesto sauce that will help you develop the intuitive skill of knowing when your pesto is just right. Although I’ve written a recipe for this spinach herb pesto below, use the quantities more as a guideline rather than gospel. Every store packages baby spinach, basil, and parsley differently. You will also base the quantity of each ingredient you use on how much pesto sauce you want to make. I wanted to make a substantial amount so I made sure to use larger amounts of spinach, basil, and parsley. Below are my tips for making a successful batch of pesto sauce. This is the method I use when I make my pesto genovese or any other variation of pesto sauce.

spinach herb pesto

The Greens
The first thing to understand when making pesto is that you should use the measurements in any given recipe as a guideline. I almost never measure my greens when I make pesto–I simply look look at the amount of greens I have on hand and go from there. Since the greens are the principle ingredient in pesto, see how much of them you have first. Then, give them a rough chop in the food processor. This will break down the greens and you will then have a better visual of the amount of pesto you will make. For the purposes of developing this recipe, I weighed each of my ingredients as I made it. I knew that spinach was my principle green, so I made sure to use a larger quantity of it. I knew I wanted a pronounced basil flavor, so I bought the largest package of fresh basil available, but since basil is an assertively flavored herb, I knew I didn’t need to match its quantity to that of the spinach. The parsley was the smallest amount of greens I used simply because I finished up what I had on hand, but also because between the spinach and basil, I had enough greens to make a substantial batch of pesto.

The Garlic
Since pesto is a raw sauce, the flavor of garlic will be pronounced, so garlic in any pesto sauce should be used sparingly and judiciously. You should be able to taste every element in a pesto sauce, from the greens, to the nuts, to the cheese, to the olive oil. Pesto sauce should never just taste of garlic. Make sure the garlic you use is fresh. Look for white, tightly closed heads that feel heavy for their size. Since the size of garlic cloves varies from garlic head to garlic head, decide how many cloves to use based on their size. Start with a small amount of garlic (maybe one clove) and add another clove if the sauce needs it. Remember: you can always add more, but you can’t take any out.

The Nuts
Pignoli (pine nuts) are my nut of choice for pesto sauce because 1.) I love them and 2.) they’re the traditional nut used in pesto sauce. But if you’ve ever shopped for a package of pine nuts, you’ve no doubt experienced sticker shock–they’re expensive! Pine nuts are one of my Italian pantry splurges but that may not be feasible for everyone. Walnuts are a more affordable and perfectly delicious substitute whose flavor pairs beautifully with the greens in spinach herb pesto. Nuts give body and flavor to the pesto sauce with their texture and natural oils. There are varying opinions about whether the nuts for pesto should be toasted or un-toasted. Italians do not toast the nuts before adding them to pesto and neither do I. Toasting nuts enhances their flavor, but the toasted flavor can be too strong in a raw, fresh sauce, so I recommend keeping the nuts un-toasted.

The Olive Oil
Extra-virgin olive oil is the best oil to use in pesto sauce since it is flavorful and rich. Fat is a principle component in a proper pesto sauce, so a richly flavored olive oil is necessary. The olive oil is what pulls the pesto sauce together once the other ingredients have been chopped and are ready to be blended. I like to add the olive oil in ¼ cup at a time to ensure that I don’t add too much. In between additions of the olive oil, I always open the lid to the food processor and scrape down the sides of the work bowl to ensure that all the ingredients are being evenly incorporated. It is also a good way to check the consistency of the pesto sauce–it should be thickly pourable but not runny, and it should never be clumpy or paste-like. All of the olive oil should be fully incorporated into the sauce.

The Cheese
There are two rules to follow about the cheese used in pesto sauce. The first rule is that pesto needs a hard, salty, aged cheese, and freshly grated Pecorino Romano or Parmigiano Reggiano are the only two cheeses used. If you can find it, fiore sardo is a milder pecorino cheese that is traditionally used in pesto genoveseand would work perfectly with this recipe too. The second rule is that the cheese is mixed into the pesto sauce only when you are ready to serve it. Don’t go overboard on the amount of cheese you grate into the sauce–how much you add will depend on how much pesto sauce you are using. Start with ¼ cup and add more if necessary. Remember that Pecorino Romano and Parmigiano Reggiano are both salty cheeses, so adding too much will make your pesto sauce too salty. Taste as you mix in the cheese to make sure you are not over-salting the pesto. If you want to freeze most of the pesto you make, simply omit the cheese from the portions being frozen.

You will notice that this spinach herb pesto uses lemon zest and lemon juice–two ingredients not found in pesto genovese, but ones that work beautifully in this pesto variation. I like the bright, fresh flavor the lemon adds to spinach herb pesto, especially since lemon pairs so well with spinach. The lemon juice also helps in preventing the pesto sauce from oxidizing and keeps it a vibrant green color.

Now that you have my tried-and-true tips for making a successful batch of spinach herb pesto, you’ll be able to welcome these first days of spring with a recipe you can enjoy throughout the season and well into summer. Buon appetito!

spinach herb pesto

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Spinach Herb Pesto

Pesto freezes very well, but if you plan on freezing it, omit the cheese and add it only when you are ready to use the pesto. For the purposes of developing this recipe, I used a kitchen scale, which is a more accurate and practical way to measure most ingredients, especially leafy vegetables. However, depending on how much pesto you want to make, use my ingredient measurements as a guideline depending on the quantity of spinach, basil, and parsley you are using.

3 ounces (86 grams) basil leaves
1 ounce (26 grams) Italian flat-leaf parsley leaves
5 ounces (142 grams) pre-washed baby spinach
2 garlic cloves, peeled and trimmed of tough ends
Zest and juice of 1 large lemon
½ cup (76 grams) pine nuts
¾ teaspoon salt
¾ cup (177 mL) extra-virgin olive oil (plus more if necessary)
Pecorino Romano or Parmigiano Reggiano (How much you use will depend on the amount of pesto sauce you are using. Mix the cheese in ¼ cup at a time and taste as you incorporate it to make sure you are not over-salting the pesto sauce.)

Remove the basil and parsley leaves from the stems and wash them in cold water. Spin the leaves dry in a salad spinner and lay them on a clean dish towel to air-dry for about 20 minutes. Blot away any remaining moisture using paper towels. Set aside.

Place the baby spinach in the bowl of a food processor fitted with the steel blade. Pulse a few times to coarsely chop the spinach. Next, add in the basil and parsley leaves and pulse a few times to chop and incorporate them into the spinach. Add in the garlic cloves, lemon zest, lemon juice, pine nuts and salt, and pulse to incorporate them into the greens. With the machine running, pour the olive oil through the feed tube in a thin stream until the pesto is smooth and thick in consistency (it should not be runny). Scrape down the sides of the bowl to ensure all the ingredients are evenly incorporated and run the machine again to properly emulsify the oil into the other ingredients.

If you will be using the pesto immediately: Transfer the amount of pesto you want to use into a serving bowl large enough to accommodate the amount of pasta you are making and stir in the cheese. As the pasta finishes cooking, ladle out about ½ cup of the hot pasta water into a heat-proof measuring cup and set it aside. Drain the pasta through a colander, add it to the serving bowl, and toss to coat the pasta evenly with the pesto. If the sauce seems too thick, dribble in small amounts of the pasta cooking water to thin the sauce gradually. It should take on a creamy consistency and cling to the pasta evenly.

Storage: If you will not be using the pesto right away, transfer it into freezer-safe containers and smooth the top surface with a spatula. Cover the surface of the pesto completely with a thin layer of olive oil and close the container tightly. Refrigerate and use within 3 days, or freeze for up to 3 months. You can also transfer the pesto sauce into an ice cube tray if you want to have smaller portions. Once the pesto cubes have solidified, pop them out and transfer them into a freezer-safe zip bag and return to the freezer.

spinach herb pesto

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1 Comment

  • Reply Lisa March 27, 2018 at 10:58 am

    I just love pesto! I’m really tempted by the idea of making it with spinach!

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