From friend and food blogger, Kate, of Kate's Kitchen
1/4 cup (1/2 stick ) butter, melted
1 cup dark brown sugar
1 egg, unbeaten
1/4 teaspoon salt
3/4 cup cake flour
1 teaspoon baking powder
1/2 teaspoon vanilla.
Preheat oven to 350º.
Pour melted butter into mixing bowl. Add other ingredients and stir till combined. Spread in buttered 8 x 8 inch pan.
Bake 20-25 minutes. Cut immediately.