01 -
Preheat the oven to 375°F (190°C).
02 -
Wipe Portobello mushroom cap with a damp cloth to remove any dirt. Remove stem and gently scrape out the gills with a spoon to create room for filling.
03 -
Place mushroom cap, stem side up, on a parchment-lined baking sheet. Drizzle with olive oil and sprinkle with garlic powder, salt, and black pepper.
04 -
Bake the mushroom cap for 10 to 12 minutes, until it begins to soften.
05 -
While mushroom is baking, melt butter in a large skillet over medium heat. Add fresh spinach and sauté, stirring occasionally, until wilted, about 3 to 4 minutes. Remove from heat and allow to cool slightly.
06 -
Transfer wilted spinach to a clean kitchen towel or paper towels and squeeze gently to remove excess liquid. Chop the spinach finely.
07 -
In a medium bowl, combine ricotta cheese, shredded mozzarella cheese, grated Parmesan cheese, and crushed red pepper flakes. Stir in the chopped spinach until evenly incorporated.
08 -
Carefully spoon spinach and cheese mixture into the mushroom cap, packing the filling gently.
09 -
Return filled mushroom to oven and bake for another 10 to 12 minutes, until cheese is melted and golden.
10 -
Remove from oven and allow to rest for 2 minutes before serving.