Presoak a clay pot, top and bottom, in water for 15 minutes.
Remove the top, seeds and pulp from tomatoes. Dry the tomato shells, then set both shells and pulp aside.
Melt the butter in a frying pan and saute the sliced mushrooms, along with the lemon juice, and salt and pepper to taste, over high heat, stirring constantly until slightly dry. Remove from the heat when you begin