Adjust an oven rack to center position. Place the butter in a 10-inch cast iron skillet and place it in the oven. Preheat the oven to 425°F. Cook the butter until it is browned and nutty-smelling, about 15 minutes (you can measure your wet and dry ingredients while waiting).

When browned, pour the butter into a heatproof cup or bowl, leaving about 1 tablespoon remaining in skillet.

Meanwhile, Combine the cornmeal, flour, brown sugar, salt, baking powder, and baking soda in a large bowl. Whisk together, making sure to break up any clumps of brown sugar.

Add the honey, eggs, sour cream, and buttermilk to a second bowl and whisk together it together, making sure the honey is incorporated.

Whisking constantly, slowly drizzle in the browned butter from the bowl.

Stir the wet ingredients into dry ingredients until just combined (do not overmix — as soon as there are no dry clumps remaining, you’re good.) If you are adding any inclusions (see the suggestions below), fold them in now.

Swirl the hot skillet to coat all surfaces with melted butter. Add a tiny drop of batter to it. It should sizzle immediately. If not, return the skillet to the oven for a few minutes to reheat it.

Scrape the batter into the hot skillet, shaking the pan slightly to even out the batter.

Transfer to the oven and bake until light golden brown on top and a wooden skewer inserted into cornbread comes out with no crumbs, 20 to 25 minutes.

Let cool for at least 10 minutes before cutting and serving. Leftover cornbread can be stored in a sealed container in the refrigerator for up to 3 days.