- Up to the temperature of 400°F, preheat the oven. As per the instructions given on the packet, cook pasta in salted water for less than 2 minutes in a large pot. Set it aside after straining. For about 3 minutes, cook it after adding broccoli. Set it aside after draining.
- On medium heat, melt 1 tbsp butter in small skillet and in this, toast the breadcrumbs. To ensure even browning, stir it with the help of a wooden spoon for about 5 minutes.
- Over medium-high heat, melt the remaining half butter in a large skillet. Add ½ tsp black pepper, leaks and garlic and for about 5 minutes, sauté it. To this, add flour and with the help of a wooden spoon, stir it. For about 2-3 minutes, cook it. Till incorporated well, whip in milk and then fold in pecorino cheese and parmesan. Turn the heat off. Mix in broccoli, pasta and chicken.
- With mozzarella and toasted breadcrumbs, top it. For about 15 minutes, bake it and then serve immediately.