Stuffed Portobello Mushrooms

Adjust an oven rack to the upper-middle position. Preheat oven to 500° F. Line a rimmed baking sheet with parchment paper or tin foil.

Arrange 8 mushroom caps, gill-side down, on a prepared baking sheet and brush each cap with 2 tablespoons of olive oil (set aside remaining 2 mushroom caps). Roast mushroom caps until tender, about 10 to 12 minutes.

While mushroom caps are baking, combine spinach, water and 1/4 teaspoon salt in a microwave safe bowl and microwave on HIGH for 2 minutes, or until spinach is wilted. Drain spinach and wrap in a clean kitchen towel. Squeeze to remove as much liquid as possible. Transfer to a cutting board and coarsely chop. Set aside.

Finely chop the 2 reserved mushroom caps. Heat 2 tablespoons oil in a large skillet over medium-high heat. Add onion and cook for about 3 minutes or until softened.

Stir in chopped mushrooms and cook about 4 minutes or until they release most of their liquid. Stir in garlic, about 30 seconds or until fragrant.

Stir in sherry and cook 2 minutes or until absorbed. Stir in chopped spinach, Gorgonzola and walnuts until heated through.

Remove the eight mushroom caps from oven, flip them gill side up, and sprinkle with 1/4 teaspoon salt and 1/4 teaspoon pepper. Divide walnut filling among roasted mushroom caps. Press down on the filling with the back of a spoon to flatten. Sprinkle with panko and drizzle 2 tablespoons olive oil. Bake 5 minutes or until panko is golden. Remove from oven and serve immediately.