In a glass jar with a screw-top lid, combine olive oil, vinegar, shallot, lemon juice, sugar, mustard, salt, and pepper. Shake vigorously to emulsify. Let stand for 30 minutes for flavors to meld. Use immediately, or refrigerate for up to a day, let come to room temperature, and shake vigorously before using.
Recipe by TeaTime Magazine at https://teatimemagazine.com/english-pea-salad-in-phyllo-shells/