Preheat oven to 350 degrees. Grease a 9 inch round cake pan.
Place bacon in a large, deep skillet. Cook over medium-high heat, turning occasionally, until lightly browned but still soft, about 7 minutes. Drain bacon slices on a paper towel. Place bacon on bottom of greased cake pan, overlapping slices as necessary to fit. Sprinkle bacon strips with brown sugar.
Mix cake batter according to box directions, adding in maple extract and maple syrup and mixing well. (If including, add blueberries in this step.) Pour batter over brown sugar and bacon in cake pan.
Bake in preheated oven until a toothpick inserted in center comes out clean, 15 to 20 minutes. Cool slightly and remove from pan by inverting onto a serving platter. Cut into wedges to serve. Maple syrup may be drilled over wedges. Makes 8 servings. Enjoy!