Portabella Mushroom Florentine Recipe

Prepare mushrooms

Preheat the broiler to high and position an oven rack 6–8 inches from the heat source. Wipe each portabella cap clean with a damp cloth and remove the stems. If desired, gently scrape out the gills with a spoon for a milder flavor and to make more room for toppings.

Make marinade

In a small bowl whisk together 2 tablespoons olive oil, 1.5 tablespoons balsamic vinegar, 2 minced garlic cloves, 1/2 teaspoon Dijon mustard, 3/4 teaspoon salt and 1/2 teaspoon freshly ground black pepper until emulsified.

Brush both sides of each mushroom cap with the marinade, reserving any extra marinade. Place the mushrooms gill-side up on a foil-lined baking sheet for easy cleanup.

Broil the mushrooms for 5 minutes to start softening and concentrating flavor. Remove from oven and brush again with reserved marinade, then return to broiler for an additional 2 minutes. Mushroom caps should be tender but still holding shape. Reduce oven temperature to broil or to 375°F (if using top-heat only, keep broiler ready for final melt).

Wilt spinach

While mushrooms are broiling, heat 1 tablespoon butter or olive oil in a large skillet over medium heat. Add 2 sliced garlic cloves and sauté 30–45 seconds until fragrant but not browned.

Add 4 cups packed baby spinach to the skillet in batches if necessary. Toss continuously until wilted, about 2–3 minutes. Season with 1/4 teaspoon salt, 1/4 teaspoon black pepper, 1/4 teaspoon red pepper flakes and 1 teaspoon lemon juice. Stir to combine and remove from heat.

Prepare tomatoes

Toss 1 cup halved cherry tomatoes with a light pinch of salt and set aside. These will be added to the wilted spinach just before assembling to keep some freshness.

Divide the wilted spinach evenly among the four broiled portabella caps, piling it into the gill cavities. Top each with the halved cherry tomatoes.

Place one slice of provolone cheese over each mushroom (if slices are large, fold to fit). Sprinkle about 1/2 tablespoon grated Parmesan over each for extra flavor if using.

Return the assembled mushrooms to the oven under the broiler for 1–2 minutes, watching closely, until the provolone is melted and edges begin to bubble. If using 375°F instead of broil, bake 4–6 minutes to melt.

Remove from oven and let rest 1 minute. Drizzle each mushroom with about 1/4 tablespoon balsamic glaze. Garnish with 1/2 tablespoon chiffonaded fresh basil per mushroom if desired.

Transfer mushrooms to plates and serve immediately as an appetizer or light main. Suggested accompaniments: crusty bread, a simple salad, or roasted potatoes.