Dutch "Boterkoek" (Butter Cake)
["1/2 lb. butter, salted", "1 1/2 c. brown sugar", "1 egg, separated", "1/2 tsp. baking powder", "1/2 tsp. salt", "2 c. white flour"]
["Cream butter and sugar. Add egg white, baking powder and salt. Add flour and mix well. Divide batter and spread into 2 pie plates. Spread egg yolk over top and decorate with cross hatching marks with the tine of a fork."]
["butter", "brown sugar", "egg", "baking powder", "salt", "white flour"]