Step 1

Place a rack in middle of oven and set skillet on rack; preheat to 450°F.

Step 2

Meanwhile, whisk cornmeal, sugar (if using), kosher salt, baking powder, and baking soda in a large bowl to combine. Whisk egg and buttermilk in a medium bowl; add to dry ingredients and mix to incorporate.

Step 3

Carefully remove skillet from oven, add lard, and swirl in pan to coat. Scrape batter into skillet (it should sizzle around edges on contact). Bake cornbread until top is golden brown and center is firm, 15–20 minutes. Let cool 15 minutes before serving.

Step 4

Spread butter over cornbread, top with chives, and sprinkle with sea salt.