These vegan stuffed portobello mushrooms are generously packed with a "cheesy" spinach ricotta filling and topped with a rich bolognese sauce to satisfy your lasagna craving.
Preheat the oven to 400℉/204℃ and line a large baking sheet with parchment paper.
Brush your mushrooms clean and scrape out the gills using a metal teaspoon. Use caution to avoid breaking the mushrooms. Then place them stem side down on your tray. Sprinkle the tops with salt and pepper and bake for 10 minutes. This step allows some moisture to escape the mushrooms so that they won't be watery later.
Meanwhile, sauté the spinach in a skillet or pan to wilt it over medium heat. Add a drop or two of water if needed to get it going. Stir often to prevent sticking. Once wilted, squeeze as much liquid out of the spinach as possible using a clean dish towel, nut milk bag, or paper towel. Set aside.
Add the ricotta cheese ingredients EXCEPT the spinach to a food processor. Process until smooth, scraping down the sides as needed. Once smooth, add the spinach and pulse 3-4 times to get it incorporated. Do NOT over-process or the cheese will turn green.
Next, combine all the bolognese sauce ingredients into a small bowl. Stir and set aside.
Remove the mushrooms from the oven and flip them stem side up. Absorb the excess moisture by blotting the mushrooms with a clean dish towel or paper towel.
Divide the ricotta between your six mushrooms. Then top each one with the bolognese sauce. Bake the stuffed mushrooms for 10-12 minutes, remove from the oven, and serve with fresh parsley, red pepper flakes, and/or vegan parmesan cheese.
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Notes
If you don't have a powerful food processor, soak the cashews in boiling hot water for 15-30 minutes, and then drain, before making your ricotta cheese.
If using frozen spinach, measure out about 1 cup and thaw and squeeze out as much moisture as possible using a nut milk bag, dish cloth or paper towels.
Do not overprocess the spinach when making the ricotta. Just pulse a few times to get it mixed in. You want to see ribbons of spinach throughout your ricotta, and not green cheese.
To make these into appetizers, use about 2-3 times as many mushroom caps or cremini mushrooms, depending on their size.
If planning ahead, make the ricotta cheese and the bolognese sauce and refrigerate them separately for 2-3 days in advance. Then stuff and bake your mushrooms the day of serving.
Leftovers will keep refrigerated for 2-3 days in a sealed container.