½ cup raw unsalted pistachios
1½ cups packed sorrel leaves, stemmed if the leaves are large
1½ cups fresh spinach leaves, stemmed
2 garlic cloves, peeled
⅔ cup extra-virgin olive oil
½ cup grated Parmesan cheese
Freshly ground black pepper
1 Tbsp. freshly squeezed lemon juice
Salt

1 ½ cups packed sorrel leaves, stemmed if the leaves are large 1 ½ cups fresh spinach leaves, stemmed 2 garlic cloves, peeled 1 Tbsp freshly squeezed lemon juice

Toast the pistachios on a baking sheet for 7 minutes at 400 degrees. Set aside to cool.
Wash and thoroughly dry the sorrel and spinach leaves.
In the bowl of a food processor, combine the pistachios, sorrel, spinach, and garlic. Pulse until everything is chopped into little bits. Add the olive oil in a slow, steady stream while the motor continues to run. Turn the motor off once all the olive oil is incorporated.
Add the grated cheese, a couple of grinds of black pepper, and the lemon juice. Process briefly to combine, taste for salt, and season accordingly.
Scrape the pesto into a bowl or container. Cover and refrigerate until ready to use.