Crunchy Corn Muffins

Name: Crunchy Corn Muffins
Ingredients: 4 tablespoons (1/2 stick) unsalted butter, melted, plus more for the muffin tin; 1 cup all-purpose flour; 2/3 cup white or yellow cornmeal; 1 1/2 teaspoons baking powder; 1/2 teaspoon fine sea salt; 1/4 teaspoon baking soda; 1/2 cup grated Parmigiano-Reggiano cheese (about 2 ounces); 1/4 teaspoon cayenne pepper; 1/2 cup whole milk; 1/2 cup sour cream; 2 large eggs