Heat olive oil in a large skillet over medium heat. Add onion and garlic and cook, stirring until softened, about 5 minutes. Add marinara sauce and tomatoes and bring to a simmer. Cook for 5 minutes, stirring occasionally.
Stir in tuna, Italian seasoning, olives, and capers. Remove from heat and season with salt and pepper. Spoon into a 2-quart baking dish.
Bake in preheated oven for 20 minutes. Sprinkle with parsley and mozzarella cheese and bake for an additional 5 minutes, or until cheese is melted.
Serve warm.
Interesting Facts
Tuna-Italiano is a great way to use up leftover canned tuna.
It’s a great dish to serve for a weeknight dinner or for a potluck.
It’s a great way to get your family to eat more seafood.