1/4 cup basil leaves
1/4 cup parsley leaves with tender stems
1/4 cup tarragon leaves
1/4 cup mayonnaise
1/4 cup sour cream
1 tsp. finely grated lemon zest
2 Tbsp. plus 1 tsp. fresh lemon juice
2 Tbsp. extra-virgin olive oil, plus more for drizzling
1 (5-oz.) can tuna in water, drained
1 celery stalk, finely chopped
1 small shallot, finely chopped
1 garlic clove, finely grated
Kosher salt, freshly ground pepper
1/2 cup coarsely chopped mixed tender herbs (such as celery leaves, basil, parsley, and/or dill)
2 English muffins, split, lightly toasted