4 cups sliced yellow onion (about 2 medium onions)
2 cups plain yellow cornmeal
1 cup all-purpose flour
1½ tablespoons chopped fresh thyme
1 tablespoon baking powder
1½ teaspoons kosher salt
2½ cups whole buttermilk
2 large eggs
Garnish: fresh thyme
Instructions
Preheat oven to 425°.
In a 10-inch cast-iron skillet, melt 2 tablespoons butter over medium heat. Add onion; cook, stirring occasionally, until soft and golden brown, 15 to 20 minutes. Reserve ½ cup onion in a small bowl. Transfer remaining onion to a medium bowl.
Wipe skillet clean. Add remaining 6 tablespoons butter to skillet, and place in oven until butter is melted and skillet is hot.
In a large bowl, whisk together cornmeal, flour, thyme, baking powder, and salt. In a small bowl, whisk together buttermilk and eggs. Stir buttermilk mixture into flour mixture just until dry ingredients are moistened; stir in onions.
Carefully pour melted butter into batter; stir until well combined. Spread batter into hot skillet; top with reserved onion.
Bake until golden brown and a wooden pick inserted in center comes out clean, 25 to 30 minutes. Let cool in pan on a wire rack for 5 minutes; serve hot. Garnish with thyme, if desired.
Recipe by Southern Cast Iron at https://southerncastiron.com/caramelized-onion-thyme-cornbread/