Preheat the oven to 400F.
Line a six-hole muffin pan with paper cups.
Heat a frying pan on the stovetop and add the chopped bacon. Cook until lightly browned. Add the asparagus and spring garlic. Cook, stirring often, for about half a minute.
Turn off the stove. Pour off the excess bacon fat. Add the butter to the pan and swirl until melted. Set aside to cool a bit.
In a bowl, whisk together the flour, baking powder, baking soda and sugar.
In another bowl, lightly beat the egg and milk.
Add the cheese to the flour mixture, breaking up large lumps and toss to coat the cheese with flour.
Add the bacon mixture and the milk-egg mixture to the flour-cheese mixture. Stir just until the dry ingredients are moistened, no more than a dozen turns.
Pour the batter into the prepared pan. Bake for 10 minutes. Lower the heat to 350F and bake for another 10 minutes.
Serve the muffins while still warm.