Gently fold egg whites into ricotta mixture. Melt butter in a 10 inch ovenproof skillet over medium high heat. Add almonds and saute 1 minute or until golden. Remove from heat.Spoon ricotta mixture evenly into skillet.
Cook about 1 minute without stirring. Transfer to oven and bake 12-14 minutes or until just set. Run a spatula around edge of cake and invert onto a serving platter. Sift confectioner's sugar over cake just before serving.Garnish with mango slices.