3 tablespoons unsalted butter, melted and cooled slightly
2 teaspoons vegetable oil
1 cup fresh blueberries or frozen blueberries, preferably wild, rinsed and dried
Whisk lemon juice, milk, and zest in medium bowl or large measuring cup; set aside to thicken while preparing other ingredients. Whisk flour, cornmeal, sugar, baking powder, baking soda, and salt in medium bowl to combine.
Whisk egg and melted butter into milk until combined. Make well in center of dry ingredients in bowl; pour in milk mixture and whisk very gently until just combined (a few lumps should remain). Do not over mix.
Heat 12-inch nonstick skillet over medium heat for 3 to 5 minutes; add 1 teaspoon oil and brush to coat skillet bottom evenly. Pour ¼ cup batter onto 3 spots on skillet; sprinkle 1 tablespoon blueberries over each pancake. Cook pancakes until large bubbles begin to appear, 1 ½ to 2 minutes. Using thin, wide spatula, flip pancakes and cook until golden brown on second side, 1 to 1 ½ minutes longer. Serve immediately, and repeat with remaining batter, using remaining vegetable oil only if necessary.