Preheat the oven to 350 degrees F (175 degrees C). Line a 12-cup muffin tin with cupcake liners.
Beat sugar and shortening together in a bowl with an electric mixer until creamy. Sift pancake mix and flour together in a separate bowl; add baking powder. Combine buttermilk and egg in another bowl.
Add flour mixture to the creamed shortening in batches, alternating with the buttermilk mixture, beating batter briefly after each addition. Mix until combined; batter should be thick, not runny. Spoon batter into the muffin cups.
Bake in the preheated oven until a toothpick inserted into a cupcake comes out clean, 15 to 16 minutes.
Cool cupcakes on a wire rack for 5 minutes. Run a table knife around the edges to loosen. Invert carefully onto a serving plate or cooling rack. Let cool, about 20 minutes.
Beat butter at high speed until creamy, about 3 minutes. Sift in powdered sugar slowly, beating until well combined. Add maple syrup, bacon, vanilla extract, and salt; mix well. Pipe buttercream onto cooled cupcakes.