Preheat oven to 190°C. Blanch 2 cauliflower heads in boiling water for 5 minutes. Sauté 2 thinly sliced shallots in 2 T butter until soft and golden. Add fresh sage, 1 T mustard and black pepper to taste. Reduce the heat and add 100 g each of Vintage Cheddar, Royal Ashton and Overberg. Stir until melted and smooth. Place the cauliflower in an ovenproof dish and pour the cheese sauce over. Grate some extra cheese over the top. Bake for 30-40 minutes, or until golden and cooked through. Enjoy!