Preheat the oven to 400°F (200°C). Grease a 12-cup muffin tin with nonstick cooking spray or line the cups with paper muffin liners.
In a large bowl, combine 1 1/2 cups yellow cornmeal, 1/2 cup all-purpose flour, 1 tablespoon baking powder, 1/2 cup granulated sugar, and 1/2 teaspoon salt. Stir until evenly mixed.
In a separate bowl, whisk together 1 cup buttermilk, 2 large eggs, 1/2 stick butter (melted and cooled slightly), and 1/3 cup pure maple syrup until blended.
Pour the wet ingredients into the dry ingredients and stir with a spatula until just combined. Do not overmix—the batter may seem wet.
Gently fold 1 cup blueberries into the batter.
Divide the batter evenly among the 12 muffin cups (they may fill to the top). Bake for 15–20 minutes, or until the tops are golden and a toothpick inserted into the center comes out clean or with a few moist crumbs.
Remove the muffins from the oven and let them cool in the pan for about 5 minutes. Run a thin knife around each muffin to loosen, then transfer the muffins to a wire rack to finish cooling.