Creamy Peppercorn Salad Dressing

1/2 cup mayonnaise, regular or low-fat
1/2 cup sour cream, regular or low-fat
1 tablespoon milk, or more as needed
1 tablespoon freshly cracked peppercorns
1 tablespoon freshly grated Parmesan cheese
1/2 teaspoon onion powder
Pinch of garlic powder
Pinch of sea salt, to taste

Whisk all ingredients to combine. Add more milk if necessary to get desired consistency. Let sit at least 30 minutes in the refrigerator to allow flavors to meld. Taste and adjust seasoning accordingly.