Preheat oven to 400°F. Line a rimmed baking sheet with foil or parchment paper. Lay bacon on top. Bake for 10 minutes, or until crisp. Let cool enough to handle.
Reduce oven to 350°F and lightly coat a 12-cup muffin tin with nonstick spray.
Meanwhile, sift together flour, baking soda, baking powder, salt, and cinnamon in a large bowl.
Whisk in milk and egg until evenly mixed. It's OK if the batter is not smooth.
Chop bacon and mix with the maple syrup, then stir into the batter. Stir in the melted butter.
Divide batter between muffin wells, using 2-3 tablespoons of batter in each. Bake for 10 minutes, let cool slightly, and serve with powdered sugar or extra syrup for dipping.