Add the oil to the 10" (25 cm) Cast Iron Skillet and place it in the oven. Preheat the oven to 425°F (220°C). Grate the cheese with the Microplane® Adjustable Coarse Grater. Whisk the buttermilk, eggs, and sugar together in a large mixing bowl. Stir in the cheese, jalapeños, and butter.In a separate small mixing bowl, combine the remaining ingredients. Add the dry ingredients to the wet ingredients and whisk together. Once the oven is preheated, carefully remove the skillet from the oven and pour in the batter. Bake for 25–30 minutes, or until the edges are dark brown and a toothpick inserted in the center comes out clean.