Preheat oven to 350 degrees F (175 degrees C). Grease and flour an 8 inch square pan. Make topping by mixing 1/4 cup sugar and 1/2 teaspoon cinnamon with 1 tablespoon butter. Set aside.
In a large bowl mix flour, baking powder and 1/2 cup sugar. Cut in shortening to a fine grain. In a separate small bowl beat egg, then pour in milk and mix together. Beat into dry mixture with minimum of strokes.
Spread batter into prepared pan and sprinkle with topping. Bake in the preheated oven for 20 to 25 minutes, or until a toothpick inserted into the center of the cake comes out clean. Serve warm.