Creamy Raw Asparagus Pesto

Name: Creamy Raw Asparagus Pesto
Ingredients: 1/2 cup walnuts, toasted (or substitute pine nuts); 1 medium clove garlic, quartered; 1/4 cup tightly packed flat-leaf parsley leaves; 3 tablespoons extra-virgin olive oil; 1/2 pound asparagus, rinsed and tough ends removed; 1/4 cup diced red onion; 2 ounces shredded Pecorino Romano (about 1 cup); 6 ounces fresh whole milk ricotta (about 3/4 cup); 1/4 teaspoon freshly ground black pepper, plus more to taste; 1/8 teaspoon table salt, plus more to taste