Preheat the oven to 375 degrees Fahrenheit.

In a large bowl, whisk together the cornmeal, flour, baking powder, and salt. In another bowl whisk together the sour cream, milk, honey, eggs, and baking soda. Gently fold the wet ingredients into the dry ones until just combined.

Place a 9-inch cast-iron skillet over high heat until hot. Melt the butter in the skillet, swirling the pan to coat the bottom and sides with butter. Pour the butter into the batter and stir to combine. Stir in the corn kernels if using. Scrape the batter into the skillet.

Bake until the top is golden and a toothpick inserted into the center comes out clean, 25 to 30 minutes.

Meanwhile, prepare the honey butter. In a small bowl, mix together the butter, honey, and lemon juice. Serve cornbread warm, slathered with honey butter.