Clean and wash the broccoli and cut it into small florets. Cover and steam in little boiling salted water for about 8 minutes. Cook the pasta in plenty of boiling salted water for about 5 minutes. Clean the mushrooms. Grate fontina cheese roughly.
Drain broccoli. Pour the pasta onto a sieve, rinse briefly in cold water and also drain. Arrange pasta and broccoli on a plate and keep warm. Put milk and fontina cheese in a pot and heat slowly while stirring constantly. When the cheese has melted, stir in the sauce thickener and heat up again briefly. Mix a little hot sauce, butter and egg yolk and stir into the rest of the sauce. Season to taste with white wine, salt and pepper. Pour sauce over pasta and broccoli. Slice the mushrooms on a fine vegetable or truffle slicer to finish.
Mix a little hot sauce, butter and egg yolk and stir into the rest of the sauce. Season to taste with white wine, salt and pepper. Pour sauce over pasta and broccoli. Slice the mushrooms on a fine vegetable or truffle slicer to finish. Season with pepper and serve immediately. Add sliced Parmesan cheese to taste