Crab-Stuffed Mushrooms

1. Stage

Preheat oven to 375°. Wipe mushrooms with a damp paper towel and remove stems; transfer stems to a medium bowl. Using a small spoon, scoop out gills and some flesh from each mushroom cap and add to bowl with stems. Arrange mushroom caps domed side down in a 13"-by-9" baking dish. Finely chop stems and scooped-out flesh.

2. Stage

In a large skillet over medium-high heat, melt 2 tablespoons butter. Once foam has subsided, add chopped mushrooms and cook, stirring occasionally, until softened, about 5 minutes. Reduce heat to medium and add scallion white parts, garlic, and 2/3 teaspoon salt. Cook, stirring occasionally, until fragrant, about 2 minutes. Add sherry, stirring until evaporated. Transfer mushroom mixture to a plate and spread in a single layer to cool. 

3. Stage

In a medium bowl, whisk egg and cream cheese until smooth. Add parsley, tarragon, 1/4 cup Gruyère, 2 tablespoons bread crumbs, and 3/4 teaspoon Old Bay and stir to combine. Fold in crab and mushroom mixture. 

4. Stage

In a small bowl, combine remaining 1/4 cup bread crumbs, 2 tablespoons Gruyère, and 1/4 teaspoon Old Bay. Melt remaining 1 tablespoon butter in the microwave, about 20 seconds, and drizzle over bread crumb mixture in small bowl, tossing with a fork until combined. Drizzle mushroom caps with oil; season with 1 teaspoon salt. Fill each cap with crab filling, mounding some extra on top. Top with bread crumb mixture.

5. Stage

Bake, uncovered, until mushrooms start to shrink and bread crumbs begin to crisp, 15 to 18 minutes. Turn on broiler and broil until topping is browned, 1 to 2 minutes.

6. Stage

Transfer mushrooms to a platter. Serve with lemon wedges alongside.