Purple kale pesto is a delicious, beautifully colored cool season alternative to basil-based summer pesto. Find out how to make your own purple kale pesto!
Pesto is a staple food in our house. In the summer, our favorite is the classic basil pesto that we make with ‘Cardinal’ basil, the most robust, open-pollinated Genovese-style basil variety we’ve ever grown. (Whether ‘Cardinal’ would perform as well in other soils and climates, we can’t say.)
We usually have the foresight to freeze plenty of summer pesto for a smattering of meals throughout the ~8 months when basil isn’t available fresh from our gardens. After all, basil isn’t fond of cool weather, owing to its tropical origins. (Genovese basil likely originated in what’s modern-day India.)
However, we also make plenty of garden-fresh pesto when the weather is downright frigid. They’re just not basil-based pestos…
Pesto doesn’t have to be made with basil
A quick bit of historical background on pesto for anyone clutching their pearls about the horrors of using anything other than basil to make pesto…
The earliest written reference to a sauce similar to pesto — moretum, one of pesto’s primary predecessors — dates back to ancient Rome. Moretum had most of the classic pesto ingredients in it, but used herbs other than basil and also included additional ingredients like vinegar.
There were other similar pesto-like Roman/Italian sauces throughout the ages but we won’t bore you with the details. Just know that each sauce had different mixes of ingredients and none of them included basil.
Pesto made with basil showed up in the mid-1800s in and around the northern Italian city of Genoa. That’s where the name for modern basil-based pestos, pesto alla genovese, comes from.
Nope, there weren’t food processors or blenders around at the time, so a mortar and pestle were used instead. Therein lies the origins of the name pesto, which is a take on the Genoan verb meaning to crush or pound.
Then, as today, there are multiple types of pesto-esque sauces varying from family to family, town to town, region to region. Here on our home in Greenville, South Carolina, we reserve the right to make pesto from a wide range of seasonally available ingredients — from purple kale to green garlic to stinging nettle!
Now, let’s dive into the nuts and bolts of making purple kale pesto.
Purple kale pesto recipe tips
Here are a few tips to help you make your own tasty and colorful purple kale pesto:
1. Which cultivar of purple kale works best?
What’s the best type of purple kale to make purple kale pesto with? The two types of kale currently growing in our garden that fall under the category of “purple” are:
- ‘Dazzling Blue’ – an open-pollinated variety whose leaves range from blueish, to purple-ish, to dark green depending on their age and cold exposure. The midribs of the leaves are always pink-purple, however.
- ‘Redbor’ – an F1 hybrid that, despite its name, is deep-dark purple throughout.
There are other cultivars of purple kale available, but between these two, we’d recommend using ‘Redbor’ for the most distinctly vibrant purple color.
‘Redbor’ also has the best flavor after it’s experienced frosts and light freezes, although beware that it’s not quite as cold-hardy as ‘Winterbor,’ its green-leafed progenitor. We lost a few Redbor plants uncovered at 17°F, whereas our Winterbors didn’t skip a beat.
2. Using Meyer lemons
We grow a lot of potted citrus, despite living in Ag Zone 7b. One of our favorites is Meyer lemons, the bulk of which ripen during the winter.
By late winter, the fruit’s skin has turned nearly orange and is so sweet throughout that you can eat them whole, similar to kumquats. We gave some of our Meyers to a citrus-loving neighbor who loved them so much, she brought them to lunch at work where she caught the attention of her co-workers for eating them whole. “These aren’t likely any lemon I’ve ever had from the grocery store,” she told us. Exactly.
The zest of very ripe Meyer lemons is equally exquisite, adding amazing flavor and color to multiple dishes, from sweet to savory.
In this recipe, we recommend using fresh Meyer lemon juice and zest. If you can’t get them fresh from a tree, get the best organic lemons you can find from a grocery store. The lemon fruit pith (the white inner skin) will add a bitter flavor to pesto — especially the longer it sits — so you’re better leaving that part of the fruit out.
3. Preserving the purple color
Other than flavor, one of the reasons we add Meyer lemon juice to this purple kale pesto recipe is to help slow oxidation, which will slowly turn the pesto from purple to more brown in color. (Same way acidic lemon juice keeps fresh-sliced apples from turning brown.)
For the most vibrant purple-colored, use your pesto as soon as possible after making it. If you want to bring back some color to purple pesto you’ve had stored in the fridge for a day or so, add a splash of fresh lemon juice and stir.
Recipe: Purple kale pesto with Meyer lemons
Purple kale pesto with Meyer lemons
A delicious cool season pesto featuring purple kale and fresh Meyer lemons. Enjoy this beautiful purple pesto on pasta, fish, or other dishes!
- 4 cups purple kale, packed
- 2 tbsp fresh Meyer lemon zest (zest from one fruit)
- 1/2 cup fresh Meyer lemon juice (juice from one fruit)
- 1/3 cup extra virgin olive oil
- 1 1/2 cups fresh-grated parmesan cheese
- 1 cup walnuts (measured whole)
- 3 tbsp white wine
- 2 cloves garlic
- salt to taste (optional but probably necessary)
First, zest your whole lemon. (It's much easier to zest before you cut into it!) Then juice your lemon. Do NOT add the pith to the pesto or it will make it bitter. (Compost it instead.)
Put lemon juice, lemon zest, extra virgin olive oil, white wine, and garlic cloves into a blender or food processor. Add the purple kale, bit by bit until fully blended.
Grate parmesan. Depending on whether your blender/processor can handle it, you can either add the grated parmesan and nuts to finish the recipe OR grind the nuts separately in a Ninja, then mix all the ingredients together in a large bowl.
Once all ingredients are blended/mixed together, add salt to taste. Quantity needed may be none or up to 1/2 tsp depending on the parmesan you use and your taste preferences.
Garnish with a touch of lemon zest and garden-fresh seasonal flowers. We used pansies, arugula flowers, and rosemary flowers. Serve over pasta, on toasted bread, or however you like. Most vibrant purple color when eaten immediately. For purple kale pesto stored in your fridge, restore color vibrancy with a splash of fresh lemon juice.
We hope you and your family enjoy this purple kale pesto recipe this winter and spring — and for many years to come!