Preheat your oven to 400°F (200°C).

In a large saucepan, cook 8 ounces of the chosen pasta in salted water, slightly undercooking it (around 2 minutes less than directed) to prevent mushiness when baking.

Once the pasta is cooked, drain it, and let it breathe while you prepare the other ingredients.

In a small bowl, add 1 cup of breadcrumbs and 2 tablespoons of melted butter. Combine well, then mix in half of the grated cheddar cheese.

In a large saucepan, pour in 1 cup of milk and 14 ounces of cream of chicken soup. Stir the mixture well until smooth.

Incorporate the diced red bell pepper, green bell pepper, celery, and the drained tuna. Mix until everything is evenly coated, then sprinkle in the remaining cheese.

Warm the saucepan over medium heat until it gently begins to bubble around the edges.

Stir in the cooked pasta into the tuna mixture, blending until well combined.

Transfer the combined ingredients to an 8 x 8 casserole dish, ensuring it’s spread evenly, and top it with the breadcrumb-cheese mixture.

Place in the preheated oven at 400°F (200°C) and bake for 30 minutes, or until the topping achieves a golden brown finish.

Remove from the oven and allow it to stand for 5-10 minutes to set before digging in.