Washed and boiled cauliflower in salted water and a little milk, then allow to drain. Heat the butter, add the flour (stirring hard) and then 250 ml water left over from cooking cauliflower. Continue stirring and add slowly the milk. Seasoned with salt and pepper and remove from heat. Allow to cool slightly and add the yolk. Cauliflower is placed in the pan, pour the sauce, sprinkle with almonds and bake in the oven until golden.