Melt the butter in a saucepan, add the flour, mix quickly, taking care not to form lumps and dilute with milk; add salt and stirring to a boil. Switch off immediately, add the saffron and mix vigorously; leave to cool. In the meanwhile divide the broccoli into small pieces and cut the stem into cubes. In plenty of boiling salted water, dip the broccoli and cook for 10 minutes. Add the pasta and continue cooking for 12 minutes, stirring occasionally. Drain pasta and broccoli and pour into a baking dish; season with 3 tablespoons of oil, add the saffron sauce, add the mozzarella and mix well. Bake in preheated oven at 200 ° with the grill function for 5 minutes; let stand 2 minutes and bring the calamarata to the table, seasoning with a ground pepper.