Preheat the oven to 350 degrees. Grease an 8-inch square baking pan.
Sift together the flour, sugar, cocoa, baking powder and the salt. Add the butter, milk, vanilla extract and chopped nuts. Stir until well mixed. Pour into the prepared 8-inch square baking pan. Mix the chocolate syrup and the hot water. Pour over the batter in the pan. Bake at 350 degrees for about 35 minutes. Makes 9 servings.