Use a 2-3 quart oven safe pan. Preheat oven to 425 degrees. Put butter in heated pan, & mix batter quickly while butter melts. Put eggs in blender & whirl at high speed for 1 minute. With motor running, gradually pour in milk, then slowly add flour; continue whirling for 30 seconds. Remove pan from oven and pour batter into the hot melted butter. Return to the oven and bake until puffy and well browned - 20-25 minutes. Dust with powdered sugar and serve at once with lemon juice or any other toppings.