Preheat the oven to 350 degrees. Butter a 9-inch square baking pan
with 1/2 teaspoon of the butter. Sift together the flour, cocoa,
baking powder and salt.
Using an electric mixer, beat the sugar and the remaining butter.
Add the egg and vanilla and beat until fluffy. Beat in the chocolate,
then the applesauce. Beat in the dry ingredients on low speed until
combined. Spread the batter in the prepared pan. Bake for about 25
minutes, or until a toothpick inserted in the center comes out clean.
Let cool, then cut into squares.