Preheat your oven to 350°F (175°C).
Boil the pasta according to the packet instructions until al dente. Drain and set aside.
In a pan, heat the olive oil and sauté the onions until translucent. Add the garlic and cook until fragrant.
Introduce the diced tomatoes and let it simmer for about 5 minutes until a sauce forms.
Fold in the drained tuna chunks. Season with salt and black pepper.
Gently mix in the fresh cream and bring to a gentle boil.
Add in the broccoli florets and let it cook for 3-4 minutes.
Mix the sauce with the cooked pasta. Ensure every bit of pasta is coated nicely.
Transfer the pasta mixture to a baking dish. Spread it out evenly.
Sprinkle the cheddar cheese generously on top.
Top it off with breadcrumbs to give that crispy finish.
Bake in the oven for 20 minutes or until the top turns golden and crispy.