Pour washed blueberries into buttered casserole (1 1/2 quart size). Sprinkle with 1/4 cup sugar. Cream 1/2 cup sugar and 1 egg together. Sift together flour, baking powder, and salt. Add this to creamed mixture alternately with 1/2 cup milk. Bake at 375 degrees for 45 minutes. Spoon out while hot and serve with whipped cream, ice cream, or milk. Serves 4 to 6.