- Preheat oven to 375°F.
- Line six 1/3-cup muffin cups with paper liners. Melt butter and cool.
- Into a large bowl sift together flour and baking powder and whisk in cornmeal, 1/2 cup sugar, lemon zest, and a generous pinch salt.
- In a bowl whisk together melted butter, milk, and yolks and add to flour mixture with half of blueberries, gently stirring until just combined.
- Divide batter evenly among cups (batter will fill cups) and press remaining blueberries into tops of muffins. Sprinkle tops of muffins evenly with remaining tablespoon sugar.
- Bake muffins in middle of oven about 15 minutes, or until tops are golden and a tester comes out clean. Remove muffins from cups and cool on a rack. Muffins keep in an airtight container at room temperature 2 days.