2 tsp. extra-virgin olive oil
12 large Baby Belle mushrooms
1 cup fresh baby spinach, chopped
1/2 yellow onion, finely chopped
2 cloves garlic, finely chopped
1 cup tomatoes, finely chopped
2 tbsp. flat-leaf parsley, chopped
salt, pepper to taste
3 tbsp. grated Pecorino/Romano/Parmesan cheese
3 tbsp. panko (Japanese breadcrumbs)
Preheat oven to 325 degrees. Line a baking sheet with parchment paper, and spray with canola oil.
Clean the mushrooms with a damp paper towel. Remove stems from mushrooms; chop the stems and set aside. Place the mushroom caps on the prepared baking sheet, cup side up, and bake for 10-12 minutes.
Meanwhile, heat the oil in a medium-sized skillet over medium heat. Add the chopped mushroom stems, spinach, onion, and garlic and saute about 5-10 minutes, until spinach wilts. Add the tomatoes and cook a few minutes more. Remove from heat and add the parsley, salt, pepper, and half of the cheese and Panko.
Remove the mushroom caps from the oven and, using tongs, carefully drain the water from them. Replace the caps on the baking dish and fill with the spinach mixture. Sprinkle stuffed caps with remainder of cheese and Panko. Place under broiler for about 5 minutes, until golden brown. Remove and serve.