Cheeseburger Quesadillas

Ingredients (12)

• ✓ ½ pound ground beef
• + ½ red onion, diced add to pantry
• + 1 clove garlic, minced add to pantry
• + 1 pinch salt add to pantry
• + 1 cup shredded Cheddar cheese, divided add to pantry
• + ¼ cup shredded mozzarella cheese add to pantry
• ✓ 1 tablespoon milk
• + 1 tablespoon butter, divided add to pantry
• + 2 (12 inch) flour tortillas add to pantry
• + 2 tablespoons Thousand Island dressing, divided add to pantry
• + 1 romaine lettuce heart, sliced add to pantry
• + 1 tomato, sliced add to pantry