The Best Copycat In-n-Out Sauce

Step 1

Use a medium to large bowl with that has a lid, and add all of the ingredients into the bowl.

Step 2

Add the mayonnaise, ketchup, sweet pickle relish, yellow mustard, white vinegar, sugar, and salt and pepper.

Step 3

Use a spoon or a whisk and mix the sauce until all of the ingredients are fully combined.

Step 4

Place the lid on the bowl, or wrap with plastic wrap, and place it in the refrigerator for at least 20 minutes before using.