Blend the Base: In a food processor, pulse the Parmigiano Reggiano, walnuts, garlic, lemon peel (or zest), salt, and lemon juice until finely chopped.
1 ounce (1/3 cup) grated parmigiano reggiano, 1/4 cup walnut halves, 2 cloves garlic, 1 - 2 pieces of lemon peel, or 1/2 lemon zested, 1/4 teaspoon Morton kosher salt, 1 Tablespoon fresh lemon juice