Preheat oven to 400 degrees. Melt butter and pour into a glass 8-inch-square pan, coating the bottom thoroughly. In a large bowl, beat eggs slightly and stir in the cheeses. Combine flour and baking powder in a separate bowl; add to egg mixture, blending thoroughly. Stir in the asparagus except tips.
Pour mixture into the baking pan, place 2 asparagus tips on each of the four servings, and bake 15 minutes. Reduce oven to 350 degrees; continue baking another 20 minutes. Cut each souffle into four pieces and serve hot.