Keto Cheeseburger Casserole

Ingredients (11)

• + 1 teaspoon butter, or as needed add to pantry
• ✓ 1 pound ground beef
• + ½ cup diced onion add to pantry
• + 2 cloves garlic cloves, pressed add to pantry
• + salt and freshly ground black pepper to taste add to pantry
• + salt and freshly ground black pepper to taste add to pantry
• + 1 cup shredded sharp Cheddar cheese, divided add to pantry
• + 2 tablespoons ketchup add to pantry
• + 2 tablespoons mayonnaise add to pantry
• + 2 tablespoons diced dill pickles add to pantry
• + ½ tablespoon mustard add to pantry