Preheat the oven to 400°F.

Add the stick of salted butter to a 9x9-inch baking dish and place in the oven until completely melted.

Toss the blueberries with 1 tablespoon flour. Reserve about ½ cup of the blueberries for topping.

In a large bowl, whisk together the 1 ½ cups flour, cornmeal, baking powder, salt, brown sugar, and granulated sugar.

In a separate bowl, whisk together the eggs, buttermilk, sour cream, oil, honey, and vanilla until smooth.

Pour the wet ingredients into the dry ingredients and stir just until combined. Do not overmix!

Gently fold 1 ½ cups of the blueberries into the batter.

Carefully pour the batter over the melted butter in the baking dish. Do not stir. The butter will rise around the sides and may pool over portions of the batter.

Scatter the remaining ½ cup blueberries over the top, gently pressing them slightly into the batter.

Sprinkle the top evenly with the turbinado sugar.

Place the baking dish on a sheet pan to catch any butter drips. Bake for 35–45 minutes, or until the top is deeply golden brown and a toothpick inserted into the center, avoiding a blueberry, comes out with a few moist crumbs attached but no wet batter. If the top becomes too dark before the center is finished, loosely tent with foil- I usually tent around 25 minutes depending on how it's looking.

Let cool in the pan for at least 20–30 minutes before slicing and serving.