Blend. Place all dressing ingredients into tall plastic cup and use immersion blender to mix until well combined, about 1 minute. Or place all dressing ingredients into food processor and blend until well combined. You can also try to mix by hand, but the cream cheese is very thick, and the dressing may not be as smooth.
1/4 cup mayo, 1/4 cup sour cream, 3 ounces cream cheese, 1/4 teaspoon dried dill, 1/2 teaspoon powdered onion, 1/2 teaspoon powdered garlic, 1/4 cup + 1 tablespoon milk, 1/2 teaspoon lemon zest, 1/4 teaspoon sea salt, 1 teaspoon lemon juice, 1 teaspoon apple cider vinegar