Melt the butter in a saucepan. Add the mushrooms and garlic and sweat. Add the beet greens and mix well. Remove pan from heat. Season with salt and pepper.
In a separate bowl, combine the egg yolks, ricotta, Parmesan cheese, and salt. Combine everything and put into a lightly oiled 9 by 11-inch baking dish. Top with the crumbled crackers and bake for 30 minutes covered. Uncover and bake for an additional 15 minutes.