Step 1

Preheat oven to 450°. Heat oil in a large ovenproof skillet, preferably cast iron, over medium-high. Add mushrooms and cook, undisturbed, until golden brown and crisp underneath, 3–5 minutes. Toss and continue to cook, tossing occasionally, until mushrooms are deeply browned all over, 4–6 minutes longer. Transfer to a medium bowl, leaving any leftover oil in skillet.

Step 2

Return skillet to medium-high heat. Add onions and cook, stirring occasionally and adding 1–2 Tbsp. oil if pan looks dry, until lightly charred all over and softened, 8–10 minutes. Add garlic and cook, stirring often, until softened but not browned, about 5 minutes. Stir in herbs and drizzle honey over, then add kale and cook, stirring occasionally, until kale has wilted and is tender, 6–8 minutes.

Step 3

Return mushrooms to skillet, season with salt, and toss to combine. Transfer mushroom mixture back to medium bowl. Wipe out skillet and place in oven to preheat.

Step 4

Combine cornmeal, baking soda, and 2 tsp. Diamond Crystal or 1 tsp. Morton salt in a large bowl. Whisk egg, buttermilk, and ½ cup melted butter in another medium bowl. Add egg mixture to dry ingredients and stir to combine. Fold in three-quarters of mushroom mixture.

Step 5

Carefully remove preheated skillet from oven and pour in remaining 1 Tbsp. butter, swirling skillet to distribute. Scrape batter into skillet. Top with remaining one-quarter of mushroom mixture. Bake stuffing until golden brown, 25–30 minutes. Serve in skillet or break into craggy pieces and transfer to a platter.