Whisk together the olive oil, orange zest, lemon zest, orange juice, lemon juice, and mustard, oregano, salt, and pepper.
4 oz olive oil, 1 teaspoon orange zest, 1 teaspoon lemon zest, ½ cup orange juice, ⅓ cup lemon juice, ¼ cup Dijon mustard, 2 tablespoon oregano, 6 cloves garlic, 1 teaspoon salt, ¾ teaspoon pepper