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.
4 slices bacon
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.
1 cup all-purpose flour, 1 teaspoon baking powder, 1/4 teaspoon fine sea salt, 1/4 teaspoon ground cinnamon
Whisk in milk and egg until evenly mixed. It's OK if the batter is not smooth.
1 cup milk, 1 large egg
Chop bacon and mix with the maple syrup, then stir into the batter. Stir in the melted butter.
2 tablespoons maple syrup, 1 tablespoon unsalted 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.