A game day version of Polish street-food zapiekanka: crispy garlic bread loaded with shredded chicken, sautéed mushrooms and onions, melty mozzarella and the classic ketchup drizzle.
Searing the chicken in the same pan before the mushrooms builds extra flavor, so don’t wipe the pan out.
Shortcut: Use shredded rotisserie chicken to skip step 3.
Make ahead: Cook the chicken and mushroom mixture up to 2 days ahead. Toast, load and bake right before serving.
Storage: Refrigerate leftovers in an airtight container for up to 3 days. Reheat in a 375°F oven or air fryer for 5 to 8 minutes.