Preheat the oven to 200C gas/ 170C fan and get out an ovenproof dish. Meanwhile, put a large pan of water on to boil for the pasta. When it is boiling rapidly, tip in the pasta and broccoli with a generous sprinkling of salt, stir and cook as directed on packet. Drain well. Put the butter, flour and milk in a large pan and heat, stir continously until it thickens to make a smooth sauce. Remove from the heat and add the mascarpone, sundried tomatoes, anchovy and basil, then add the pasta and broccoli and season well. Bake for 30 minutes until the mixture is just starting to bubble round the edges and the mixture is pale golden – don’t let it go too dark or the fish will overcook.