Maple Tuna Olive Toastie

Ingredients (9)

• + 2 tablespoons butter add to pantry
• + ½ large sweet red onion, thinly sliced add to pantry
• + 1 tablespoon maple syrup add to pantry
• ✓ 2 (5 ounce) cans tuna, drained
• + 2 tablespoons creamy salad dressing (such as Miracle Whip®) add to pantry
• ✓ salt and ground black pepper to taste
• + salt and ground black pepper to taste add to pantry
• + 1 (12 ounce) loaf Italian olive bread add to pantry
• + 8 ounces shredded Cheddar cheese add to pantry