1 tablespoon (15 grams) unsalted butter, room temperature
1-1/2 cups (192 grams) all-purpose flour
1 cup (150 grams) cornmeal
2 tablespoons (30 grams) granulated sugar
1 tablespoon (15 grams) baking powder
1 teaspoon (5 grams) salt
1 cup (236 milliliters) buttermilk
1/4 cup (60 grams) mayonnaise
1/3 cup (75 grams) unsalted butter, melted
3/4 cup (94 grams) grated cheddar cheese
1 green onion, thinly sliced
Heat oven to 350°F (176°C). Grease 23 centimeter cast iron skillet with room temperature butter. Place skillet in oven.
Combine flour, cornmeal, sugar, baking powder and salt in a large bowl.
Whisk together buttermilk, eggs and mayonnaise in a medium bowl. With a rubber spatula, make a well in the centre of the dry ingredients. Add buttermilk mixture along with melted butter and stir just until combined. Fold in the cheddar cheese and green onions. Allow batter to sit at room temperature for 20 minutes.
Retrieve skillet from oven and carefully pour the batter into pan. Bake for about 25-30 minutes, until a toothpick inserted into the middle comes out clean. Cool for 20 minutes before cutting to serve.