Stuffing-Stuffed Mushrooms

Heat the oven to 400 degrees and lightly brush a large rimmed sheet pan with olive oil.

Using barely moist paper towels, wipe the mushroom stems and caps clean. Carefully tear off the mushroom stems, setting them aside in a medium bowl. Set each mushroom cap on its side and slice off the excess mushroom cap that curls over the gills. (The goal here is to create a flatter surface area so the mushrooms caramelize instead of steam, and so you can pile more stuffing on top.) Transfer the mushroom scraps to the bowl with the mushroom stems, then transfer the trimmed mushroom caps to the sheet pan, cut-side up.

Brush the tops of the trimmed mushrooms with 3 tablespoons oil. In a small bowl, stir together the garlic powder, onion powder, 1/2 teaspoon salt and 1/2 teaspoon pepper; sprinkle the mixture over the tops of the mushrooms. Flip the mushrooms so they are cut-side down, and roast until they have released their liquid and are starting to caramelize, about 15 minutes. Remove sheet pan from heat, and set aside.

While the mushrooms roast, prepare the filling: Finely chop the mushroom stems and scraps or transfer them to a food processor and pulse until finely chopped. (You will have about 2 cups.)

In a large skillet, melt the butter over medium-high heat. Add the chopped celery, shallots, garlic, rosemary, poultry seasoning and celery seeds. Season generously with salt and pepper, and cook, stirring, about 5 minutes. Add the chopped mushrooms, season with salt and pepper and cook over medium-high, stirring occasionally, until caramelized and tender, 4 to 5 minutes. Transfer vegetable mixture to a large bowl to cool, at least 15 minutes.

Once the vegetable mixture has cooled, stir in the cornbread, cheese, celery leaves and 3 tablespoons chopped parsley. Season generously with salt and pepper. Whisk the eggs together in a small bowl, then stir into the cornbread filling until combined. (Makes about 4 cups.)

Wipe the sheet pan clean, then brush again with olive oil to coat. Mound about 1 to 2 tablespoons filling into each mushroom cap, patting them gently without packing them tightly, then transfer to the sheet pan, spacing them evenly apart. Bake until mixture on top is warmed through, 10 to 15 minutes. Broil until browned in spots, 2 to 4 minutes. Let cool a few minutes, then transfer to a serving platter and sprinkle with remaining 1 tablespoon minced parsley to serve.