Ingredients
1 3/4 cups unbleached all-purpose flour
1/4 cup fine cornmeal
3/4 cup sugar, plus more for sprinkling (optional)
2 teaspoons baking powder
1 teaspoon kosher salt (we use Diamond Crystal)
4 ounces rhubarb, cut into a 1/2-inch dice (1 cup)
4 ounces blueberries (a scant 1 cup)
2 large eggs, room temperature
3/4 cup whole or 2 percent milk, room temperature
1 stick unsalted butter, melted and slightly cooled
1 teaspoon pure vanilla extract
Preparation
Preheat oven to 350°F. Line a standard 12-cup muffin tin with baking cups. In a medium bowl, whisk together flour, cornmeal, sugar, baking powder, and salt. Reserve about 3 tablespoons each rhubarb and berries, then stir the rest into mixture. Create a well in center of mixture; add eggs and whisk. Whisk in milk, butter, and vanilla.
Divide batter evenly among muffin cups, about 1/3 cup each (they will be very full). Press a few pieces of reserved fruit into top of each, then sprinkle with sugar. Bake until tops spring back when lightly touched, 25 to 30 minutes. Let cool 5 minutes in tin, then remove muffins and transfer to a wire rack; let cool completely, about 30 minutes.
