Asparagus Upside Down Corn and Cheddar Muffins

Name: Asparagus Upside Down Corn and Cheddar Muffins
Ingredients: Butter for greasing muffin tins; 2 tablespoons butter, chopped into 12 small pieces; 1 small bunch of asparagus, trimmed and sliced on the diagonal (see picture); 1 cup corn flour; 1 cup whole-grain pastry flour; ¼ cup dark brown sugar; 2 teaspoons baking powder; ½ teaspoon baking soda; 1 teaspoon kosher salt; 2 cups grated sharp cheddar cheese; 1½ cups sour cream; 2 eggs; 2 ounces unsalted butter, melted and cooled slightly