Lemon Pesto (Pesto di Limone)

This will be your go-to pesto for sandwiches, pastas, seafood and salads. Its bright, refreshing and lemon forward with a modest garlicky undertone, nutty flavor and toothsome bite from the almonds.

Origins: Amalfi Coast

Amalfi lemons, also known as Sfusato Amalfitano, are an Italian Protected Geographical Indication product. They are produced exclusively on the picturesque Amalfi coast and are famous for their intense lemon aroma, unique shape and light yellow color. Their cultivation dates back to 900 AD. Amalfi lemons are prominently used in a liqueur called Limoncello. Unfortunately, these are virtually impossible to get Stateside so use any large lemon you like.

This pesto seems to originate from an Amalfi coast dish called spaghetti al pesto di limone. There is also a relation to spaghetti al limone a creamy pan sauce lemon pasta dish. It was very difficult to find lemon pesto reference recipes online. I also did not come across it in restaurants during my travels to the Amalfi coast.

Most of the online recipes were more pastes than pestos, the latter of which is supposed to be saucy. I was ultimately introduced to lemon pesto through a Tiktok video which praised the virtues of Trader Joe’s lemon pesto sauce. I then set out to create my own version which stayed true to the techniques and saucy consistency of Pesto Genovese (basil pesto).

Lemon Zest

Lemon zest, also known as flavedo, is the colored outermost peel of the lemon (or citrus fruit) which does not include the white, spongey and bitter pith, also known as albedo. Limonene is the terpene responsible for the zesty citrus fragrance of lemon but it is also found in oranges and other citrus fruits.

Zesting Lemons

Use a Y-peeler and large lemons for this recipe. Small lemons are more difficult to peel uniformly with a Y-peeler. Using a microplane aggressively and unevenly scrapes the lemon zest off causing much of the essential oils to go airborne. In contrast, a y-peeler gently peels the zest off in a way that leaves the majority of the lemon’s oils intact.

This is not to say that microplaned zest has no use generally. Microplaned zest is my goto for quick final additions to recipes. However, for a dish in which lemon flavor and the look of the zest in the pesto sauce are so integral to its construction, we want to make sure we do everything technically possible to ensure we utilize the zest as efficiently as possible. Also, so as not to interfere with the lemon flavor, we opt for neutral oil (sunflower or grapeseed) as opposed to fragrant oils like olive or vegetable oils.

Sidebar: De-wax your Lemons

Many lemons come from the grocery store with a layer of protective wax on them. This is generally not harmful but could interfere with the flavor and consistency of the pesto. To remove it use very hot water and soak or rinse the lemons under it until the layer of wax is softened.

Next, gently scrub the lemons with a clean brush under the hot water or while rinsing it with hot water to remove the wax.

After removing the wax, rinse and pat them dry with a clean towel. Now they are ready to use in the pesto. You can also use any other method of wax removal which suits your preferences.

Pesto Science

Pesto is an emulsion. Its name is derived from the Geonoese verb pestâ which means “to pound.” When we pound the garlic in a mortar and pestle we destroy its cellular integrity and activate garlic’s defense mechanism: the release of allinase.

Allinase kicks off the production of allicin which mixes into the garlic’s oil creating the characteristic sulfur-rich flavor and aroma of garlic. Slicing garlic, even finely, is much less of a traumatic break down of garlic’s cell wall structure, hence resulting in a less pronounced garlicky flavor.

Pesto’s emulsion (in basil pesto) is further enriched by the the high free fatty acid content in pine nuts and release of water and phospholipids from pounded basil leaves. To add to basil pesto’s water content, many chefs rinse the basil without drying it to achieve their desired pesto consistency. Moreover, pesto is a sauce and not a paste.

This is why my recipe includes a small amount of water in addition to the lemon juice. We need the water to take this pesto from paste to sauce. Do not replace the water with more lemon juice. It is ok to add a squeeze or two more lemon juice to suit your tastes but you do not want to go overboard on the acidity of this pesto.

Mortar and Pestle vs. Food Processor

I recommend using a mortar and pestle. The quality in flavor, mouthfeel, and emulsion was superior in lemon pesto test recipes made in the mortar and pestle. The tedious process of pounding a pesto’s ingredients in a mortar and pestle extract greater flavor than the high speed mincing of a food processor. There is simply no shortcut to amazing pestos.

The type of mortar and pestle that is ideal for pestos is a marble mortar and wooden pestle. I very seldom make pestos so a large molcajete suits my needs in terms of price, size and versatility.

Food processor lemon pestos were particularly more grainy and gritty and less emulsified than the lemon pestos I finished in the mortar and pestle.

While the food processor was great at making quick work of the pesto’s components, the breakdown was only a very fine mince. It was far short of the creamy and saucy consistency derived from the mortar and pestle.

The flavor of food processor lemon pesto was still good but it was not as good as the mortar and pestle version.

To Toast or not to Toast

In Pesto Genovese (basil pesto) there is a fairly large consensus that toasting pine nuts makes no difference in the final pesto. In my experience with Pesto Genovese I also found this to be true.

However something magical happened when I toasted the raw sliced almonds before using them in my lemon pesto. A toasty and fragrant aroma emerged that was deep in flavor and reminiscent of fried chicken skin. The toasting of almond’s natural oils and skins added a deeply nutty and aromatic component to the pesto.

When toasting the almonds you are not looking for a huge difference in color. The indicator of completion should be the aroma and a faint crackling noise made by the almonds as they toast. Overall, toasting the almonds makes a difference. I highly recommend doing so.

Pecorino Romano or Parmigiano Reggiano?

I recommend using Pecorino Romano. Pecorino Romano is salty, tangy with grassy and earthy undertones. Its the perfect pair to the aromatic and floral lemon flavors. Parmigiano Reggiano on the other hand is nutty, fruity and almost caramelly.

The flavors of Parmigiano Reggiano merely double down on notes already present in the lemon pesto (i.e fruitiness from lemons and nuttiness from almonds). Pecorino Romano offers a better contrast to the fruity and nutty notes while adding to the brightness. This gives the resulting lemon pesto a greater level of complexity and depth.

There is no harm in swapping one for the other or using half and half. Your house your rules.

Tips for using a food processor

DONT. LOL JK

• Process the almonds to as fine a mince as possible before adding the garlic and water.
• Before adding the garlic and water, grate the garlic over a microplane or crush the garlic into a paste then combine it thoroughly with the water before adding the garlic and water to the minced almonds.
• Skip the rough chopping of the lemon zest before adding it to the food processor.

Lemon Pesto

Chef Way

Light, creamy, refreshing and bursting with lemon flavor.

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Equipment

• 4 cup molcajete
• 8 cup food processor
• Y peeler
• Budget Y peeler
• Matfer Bourgeat Black Carbon Steel Fry Pan (8 5/8)

Ingredients

  

• 80 g raw sliced almonds (¾ c)
• 3 garlic cloves (15-18 g)
• Zest of 1 lb large lemons roughly chopped (~35 g of peeled zest)
• 180 mL sunflower oil (¾ cup / 6 oz)
• 60 mL lemon juice (¼ cup / 2 oz)
• 60 mL water (¼ cup / 2 oz)
• 85 g Pecorino Romano finely grated
• 3 g pink Himalayan or sea salt finely ground (½ tsp)
• 2.5 g granulated sugar (½ tsp)
• Black pepper to taste freshly cracked

Instructions

 

• In an 8-inch pan or skillet, toast almonds over medium-high heat until they release a fragrant toasty aroma. Toss the almonds every minute or so. This should take about 12 minutes over medium heat and 7-8 minutes over medium high heat. When the almonds finish toasting, remove them from the heat and place them on a tray to cool for about 10 minutes.
  
• In a 4-cup molcajete add the garlic and salt. Mash this into a fine paste. This is a key step that ensures the proper emulsification of the pesto.
  
• Add the water to the garlic paste and mix the garlic paste in until it is fully incorporated.
  
• Next add the almonds to the molcajete and mash them into smaller bits.
  
• Add the lemon zest and continue to mash the mixture until the almond and lemon zest begin to approach uniformity in size.
  
• Add about ¼ of cup of your oil and begin to work the mixture into a very rough paste.
  
• Once that oil is fully incorporated, add all of your Pecorino Romano and work that in until the mixture is a dry-ish white pale paste
  
• Add the remaining oil to the molcajete. You can do so by gradually streaming it and incorporating it with the pestle or by adding it in all at once then gently stirring with the pestle to incorporate it. The latter is a bit easier due to how thick the mixture is.
  
• Once the oil is well incorporated add the freshly cracked black pepper, sugar and lemon juice.
  
• Stir this in with the pestle until a beautiful creamy pesto emerges.
  
• Use or freeze within 3-7 days.