Preheat oven to 375 F. Lightly grease a 9-inch baking dish with melted butter.
In a medium mixing bowl, combing milk, sugar, flour, egg whites, egg, vanilla, cinnamon, nutmeg and salt. Whisk ingredients together until blended and frothy, 5 to 10 minutes.
Pour 1/3 of the batter into the prepared dish. Bake 2 minutes in preheated oven, then remove. Layer sliced apricots over batter and top with remaining batter. Return to the oven and bake until the center is just set and the edges are golden brown, 40 to 45 minutes. Remove from oven and cool on wire rack. Dust with confectioner's sugar and serve. Makes 6 to 8 servings.