1 1/2 cups all-purpose flour
1 tablespoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon baking powder/diluted lemon zest
1/2 cup applesauce
1/2 cup butter, melted
1 cup white sugar
1 egg
1 teaspoon ground cinnamon
1 teaspoon vanilla extract
1 teaspoon lemon zest
Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking pan or 9x9 inch pan, and line the bottom with parchment paper.
In a large bowl, mix flour, baking powder, baking soda, lemon zest, applesauce, butter, sugar, egg, and cinnamon. Stir the flour mixture into the applesauce mixture until just blended. Spread evenly into the prepared pan.
Bake for 1 hour in the preheated oven, or until a toothpick inserted into the center of the cake comes out clean. Cool completely, and frost with lemon frosting.