1. Gently clean the mushrooms using a damp cloth and remove the stems. Lightly brush the caps with olive oil and place them gill-side up on a parchment-lined baking sheet. Preheat your oven to 375°F (190°C).

2. In a non-stick skillet over medium heat, add 1 tablespoon olive oil. Sauté the onion until soft, about 3 minutes. Add the garlic and cook until fragrant, then add the spinach. Cook until wilted, then transfer the mixture to a bowl to cool slightly.

3. Using the same skillet, add a splash of olive oil and cook the chopped shrimp just until they start to turn pink (1–2 minutes). Add them to the bowl with the spinach. Gently fold in the crab meat, cream cheese, sour cream, Old Bay seasoning, lemon juice, paprika, salt, and pepper. Stir just until combined.

4. Fill each mushroom cap generously with the seafood-spinach mixture. Top with a sprinkle of Parmesan cheese and panko breadcrumbs. Optionally, place a whole sautéed shrimp on top of each cap.

5. Bake the stuffed mushrooms for 18–20 minutes, or until the tops are golden and the filling is hot. For extra crispiness, broil for the last 2–3 minutes while watching closely.

6. Remove from the oven and let cool for 5 minutes. Sprinkle chopped parsley on top and serve warm, with an optional drizzle of lemon juice or garlic butter.