Step 1

Preheat oven to 400°F with a baking tray inside.

Step 2

In a small saucepan over medium heat, heat the olive oil. Add the onions, mushroom stems and garlic and cook until fragrant and slightly reduced, about 5 minutes. Add the thyme and walnuts, and cook to toast the walnuts lightly, about 1 minute. Remove from heat and set aside.

Step 3

In a small bowl, combine the chickpeas, parmesan cheese, parsley, salt and pepper. Use a fork to combine and mash the chickpeas to form a paste-like texture. Transfer the nut mixture on top of the chickpea mixture and stir to combine.

Step 4

Carefully place the mushrooms on the hot tray and spray with cooking spray. Spoon the filling into the mushrooms, and top with the remaining parmesan cheese.

Step 5

Bake the preheated oven uncovered until the mushrooms are cooked through and the cheese has melted, about 15 minutes. Serve warm.