01 -
Preheat your oven to 200°C. Spray a 23x33 cm baking dish with cooking spray and set aside.
02 -
Bring a large saucepan of water to a simmer. Add the broccoli and 1 teaspoon salt. Cook uncovered for 5 minutes, until crisp-tender. Drain and set aside.
03 -
In the same saucepan, heat the oil over medium heat. Add the onion and cook for 4 minutes, stirring frequently, until translucent and fragrant. Add the garlic and sauté for another 30 seconds. Return the cooked broccoli to the saucepan and stir to combine everything, then remove from the heat.
04 -
In a medium mixing bowl, combine the tuna and crème fraiche. Season with the remaining teaspoon of salt and black pepper, adjusting to taste if needed.
05 -
Place the broccoli mixture, tuna mixture, and halved cherry tomatoes into the prepared casserole dish. Stir to combine. Sprinkle with the shredded cheddar cheese and top with the sliced mozzarella cheese.
06 -
Bake the casserole uncovered for 15 minutes, until the sauce is bubbling and the cheese has melted and looks golden brown.
07 -
Take the casserole out of the oven and let cool for 10 minutes. Garnish with fresh basil leaves and a few cracks of black pepper if desired. Serve warm.