1. Preheat the oven to 425°F. Spray 18 standard-size or 12 large muffin-tin cups with oil, or line the cups with papers.

2. Stir together the flour, blue cornmeal, salt, baking powder, and baking soda into a large bowl. Set aside.

3. Cream together the butter and sugar in a small bowl, then beat in the egg, vanilla, and nutmeg.

4. Stir the creamed mixture into the dry mixture along with the milk, until not quite blended. Then add the blueberries and the walnuts, if using, with just a couple of strokes, so the mixture is just barely combined. Spoon into the prepared muffin cups.

5. Bake until the edges of the muffins are golden brown and the caps are rounded and also golden, 22 to 27 minutes. Let cool for just a few minutes, then remove from the cups. Serve warm (or rewarm before eating them) with Blueberry-Cream Cheese-Honey Butter, if you like

Variation: Blueberry-Walnut Streusel Muffins

Substitute brown sugar for white in the muffin batter; pass on the optional walnuts. Make the streusel topping: Cut together 2 tablespoons butter, 3 tablespoons brown sugar, 2 tablespoons unbleached white flour, and 1 tablespoon oatmeal until crumbly. Toss in 1/3 cup chopped toasted walnuts. Divide this mixture among the tops of the unbaked muffins. Bake as directed.