In a mixing bowl, combine cornmeal, all-purpose flour, baking powder, cornstarch, and kosher salt. Whisk until evenly blended.

In a stand mixer, beat softened butter, brown sugar, granulated sugar, and honey until fluffy and light, about 2-3 minutes.

Add eggs and vanilla extract to the creamed mixture. Mix on low until fully incorporated.

Gradually add the dry mixture into the wet ingredients, mixing on low until just combined.

Roll about ¼ cup of dough for each cookie into balls and flatten slightly. Place on a baking sheet with 2 inches apart.

Preheat oven to 350°F (175°C) and bake for 11-14 minutes until edges are golden brown.

Cool on baking sheets for 5 minutes, then transfer to a wire rack to cool completely.

In a mixing bowl, beat softened butter, honey, powdered sugar, and vanilla until smooth. Adjust consistency with water if needed.

Frost cooled cookies with buttercream and sprinkle with flaky sea salt.