Preheat the oven to 400 degrees F (200 degrees C). Butter a 9x9-inch square baking dish.
Whisk melted butter, honey, 2 tablespoons sugar, lemon zest, and salt together in a large bowl until combined. Whisk in eggs until incorporated. Add milk and lemon juice, and whisk until combined (mixture will look curdled, this is fine). Add 1 cup flour, cornmeal, and baking powder, and whisk until smooth and combined.
Toss blueberries and remaining 2 tablespoons flour together in a separate bowl. Add blueberries to the batter and fold until incorporated.
Pour batter into the prepared pan and spread into an even layer. Sprinkle remaining 2 tablespoons sugar over the batter.
Bake cornbread in the preheated oven until a toothpick inserted into the center of the cornbread comes out clean, 20 to 25 minutes. Cool cornbread in the pan for 15 minutes before removing to a wire rack. Can be served warm or at room temperature.
