1-Getting started with this spinach stuffed portobello mushrooms recipe is fun and straightforward. Begin by whisking together 2 tablespoons extra virgin olive oil, 1 tablespoon balsamic vinegar, and 2 cloves garlic to make a flavorful marinade. Coat the 4 large mushroom caps with this mixture and let them rest for 15 minutes to soak up the flavors.

2-Preheat your oven to 450ºF for the best results. Place the mushrooms stem side down and bake for 10 minutes to start. While they bake, mix 10 ounces of defrosted frozen chopped spinach with ¼ cup Parmesan cheese, 2 to 3 tablespoons heavy cream, and season with coarse kosher salt and freshly ground black pepper.

3-After the initial bake, flip the mushrooms, spread the spinach mixture evenly on top, and add 1 cup shredded mozzarella cheese along with the remaining Parmesan. Pop them back in the oven for another 10 minutes until the cheese melts and browns beautifully. This method ensures a hearty, cheesy finish that’s hard to resist.

4-Follow these steps closely for a seamless experience. First, prepare the marinade as described. Second, bake the mushrooms initially to release moisture. Third, combine the filling ingredients thoroughly. Fourth, stuff and top the mushrooms carefully. Finally, finish baking for that perfect golden touch, adapting for vegan options by using substitutes.