Preheat over to 325 degrees Fahrenheit.
Lightly grease an 8" x8" baking pan.
Melt butter in a microwave safe dish. Set aside and let cool. Using two separate bowls, separate eggs, yolks in one bowl and whites in the other.
Beat egg whites until stiff. Set aside. Whisk powdered sugar into yolks, then add butter, sugar, water, milk, and almond extract. Blend well. Slowly add flour until incorporated.
Gently fold in egg whites, a little at a time, until blended. Pour batter into prepared pan and bake for 40 minutes. Note: Cover with foil if top browns too quickly.
Test with a toothpick in center of dessert. Cake is done when the custard center is just set. Do not overcook.
Remove from oven and cool completely. Before serving, dust with powdered sugar.