Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch cake pans.

Stir cake mix, water, oil, and eggs together in a large bowl until moistened; beat with an electric mixer on medium speed for 2 minutes. Pour cake mixture into prepared pans.

Bake in the preheated oven until a toothpick inserted near the center comes out clean, about 30 minutes; cool completely, about 30 minutes.

Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned and crisp, about 10 minutes. Drain bacon slices on paper towels. When cool enough to handle, crumble bacon into a small bowl.

Beat butter until creamy with an electric mixer in a bowl; slowly beat in 2 cups confectioners' sugar until well blended. Beat maple syrup and vanilla extract into butter mixture until smooth and creamy; beat in remaining confectioners' sugar as needed until frosting mixture is a spreadable consistency. Fold crumbled bacon into frosting.

Place one cake layer on a serving plate; spread about 1/2 cup bacon frosting evenly over cake. Place second cake layer over the first; spread remaining frosting evenly over sides and top of cake.

Draw or print a maple leaf shape on a piece of paper. Fold the page in half down the center of the leaf; cut along the outline so that you will have a hole in the paper in the shape of a maple leaf. Center the paper on top of the frosted cake; press down slightly on the cut edges. Sprinkle the open area with red sugar; gently remove the paper stencil.