1/4 tsp. freshly ground black pepper
1/2 tsp. kosher salt
1/2 tsp. white wine vinegar
1 tsp. ground coriander
2 tbsp. fresh lemon juice
2 tbsp. coarsely chopped walnuts
2 tbsp. olive oil
1/4 cup water
1/2 cup fresh cilantro leaves
1/2 cup fresh flat-leaf parsley leaves
1/2 ripe avocado