Yield: 6-8 servings.
¾ cup + 2 tablespoons unsalted butter
1 medium sweet onion, thinly sliced
1½ teaspoons salt, divided
Freshly ground black pepper
4 Pink Lady apples, peeled, cored, and thinly sliced
1 teaspoon dried thyme leaves
1 teaspoon ground sage
4 tablespoons brown sugar, divided
1½ cups cornmeal
1 cup all-purpose flour
1 tablespoon baking powder
2 large eggs
1½ cups buttermilk
5 sprigs fresh thyme
Preheat oven to 400°. Melt all of the butter in a cast-iron skillet over medium-high heat. Pour all but 2 tablespoons into a small bowl; set aside.
Add onion to butter in skillet; season with ½ teaspoon salt and pepper, and cook, stirring occasionally, until onion begins to brown (about 4 minutes). Add apples, dried thyme, sage, and 2 tablespoons brown sugar, stirring often, until apples are softened. Transfer apple mixture to a medium bowl and set aside.
Whisk cornmeal, flour, baking powder, 1 teaspoon salt, and remaining 2 tablespoons brown sugar in a large bowl. Gradually whisk in eggs, buttermilk, and ¾ cup reserved melted butter until batter is smooth. Fold in half of apple mixture and scrape batter into cast-iron skillet. Top with remaining apple mixture and fresh thyme sprigs.
Bake cornbread in preheated oven for 30 to 40 minutes or until edges are golden brown. A knife inserted into the center should come out clean. Let cornbread sit for 5 minutes before serving.