Bacon leek and broccoli gratin

2) Melt the butter in a pan and add the flour to make a paste.
3) Add the milk whisking until you have a thick sauce that coats the back of a spoon.
4) Add 80% of the grated cheddar and stir until melted.
5) Fry the bacon, garlic and sliced leek until lightly browned.
6) Add the bacon and leek mixture to the cheese sauce and season to taste.
7) Arrange the broccoli in a roasting dish and pour over the sauce.
8) Sprinkle the remaining cheddar and Parmesan over the top and bake for 30 minutes until golden.