Saute mushrooms in 3 Tbs butter until limp. Stir in the crushed crackers, then turn into well greased 10-inch round quiche pan. Press mushroom mixture evenly over bottom of dish and up the sides. Melt remaining butter, add onions, saute and add shredded Spam. Layer shredded cheeses and Spam in dish. In blender, whirl the eggs, ricotta, milk and cayenne until smooth. Pour into crust and sprinkle with paprika. Place sauteed red and green bell peppers on top. Bake in oven at 375 for 40 to 45 mins. Garnished with cooked artichoke.