This is an old recipe that I found in my late MIL's recipe box. Some of the recipes were newspaper clippings that were so yellowed from time I could hardly read them Fortunately, this one I could! Try it!
Mix beans, mushrooms, onion, garlic and cheese in pie plate. Beat remaining ingredients until smooth, 15 seconds in blender on high speed or 1 minute with hand beater. Pour into pie plate.Bake until golden brown and knife inserted halfway between center and edge comes out clean, 30 to 35 minute Let stand 5 minute before cutting. Refrigerate any remaining pie.