1. In a bowl, mix flour, cornmeal, sugar, baking powder, and salt. In another bowl, beat eggs to blend with buttermilk and 1/4 cup butter. Pour liquids into flour mixture and stir just until evenly moistened.
2. Spoon half the batter equally into 12 buttered 2 1/2-inch muffin cups. Top each portion with 2 teaspoons habanero or jalapeño jelly. Fill cups equally with remaining batter.
3. Bake in a 400° oven until muffins spring back when lightly pressed in center and are lightly browned, 20 to 25 minutes. Serve hot or cool.