shallots, finely chopped
fresh mushrooms, sliced
Cube potatoes and roast in oven until softened and just golden brown - Don't let them get too mushy.
In a skillet, melt butter and saute shallots.
Stir in flour and cook 3-5 minutes stirring constantly.
Add cream and stir until thickened, then add the mushrooms, salt and cayenne and cook for about 3 minutes.
Beat sherry and egg yolks together and quickly stir into the hot mixture.
Put the potatoes in an ovenproof baking dish, and pour the Thermidor sauce over potatoes.
Bake at 300 for 20 minutes to heat thoroughly.