Preheat oven to 375°F.
In a medium bowl, whisk together flour, baking soda, salt, cinnamon and sage.
In a small bowl, combine 2 tablespoons of the oats with cheese.
In a large bowl, stir together buttermilk and remaining oats and let stand for 5 to 10 minutes to let the oats soften.
Stir in brown sugar, egg and butter until combined. Add dry ingredients and stir just until moistened; fold in diced bacon.
Evenly divide the batter between the wells of a 12 cup muffin tin lightly coated with nonstick spray. Sprinkle tops with oat-cheese mixture.
Bake until lightly browned and a toothpick placed in the center comes out with a few moist crumbs attached, about 18 to 20 minutes. Remove and let stand for 5 minutes before transferring the muffins to a wire rack. Serve warm.
Makes 12 muffins.