Ingredients
Method
- Preheat oven to 375°F (190°C). Cook noodles to al dente, drain, and set aside.
- Sauté onion in butter over medium heat until soft, about 4 minutes. Stir in mustard, soup, milk, salt, and pepper.
- Fold in tuna, peas, and noodles. Transfer to a 9x9-inch baking dish and smooth the top.
- Toss sourdough cubes with oil and garlic powder, then spread over casserole. Bake 20–25 minutes until bubbly and croutons are golden.