In an 8- or 9-inch skillet, heat 1/2 tablespoon of the oil until shimmering. Scrape the batter into the skillet, smoothing the surface. Cover partially and cook over moderately low heat until the corn cake has browned on the bottom and bubbles have formed on the surface, about 5 minutes. Using a large metal spatula, transfer the cake to a dinner plate. Add the remaining 1/2 tablespoon of oil to the skillet. Gently invert the cake into the skillet, partially cover and cook until the cake is just cooked through and the top springs back when lightly pressed, about 5 minutes longer. Serve hot, with butter and maple syrup.