What is the difference between a portobella mushroom, a cremini mushroom, and a white button mushroom (all of which are readily available at your local produce market)? Nothing…except maturity, and perhaps as much as $3 or $4 per pound. They are the same species - just harvested at different stages of their growth cycle. But unless you are planning a dinner party and want hors d’ oeuvres, the extra price to buy about six mature portobella mushrooms for this recipe is well worth the reduced prep time compared to hollowing and stuffing about twenty or more of the smaller variety.
We’re going to stuff these with a mixture of spinach, ground beef, tomatoes, onions, garlic, sun-dried tomatoes, and more mushroom (actually just the stems and gills from the mushroom caps). You could mix this recipe up a bit by using different sausages in place of the beef, and adding other ingredients with flavors that are unique enough to stand on their own and add interest to the stuffing – perhaps minced olives, or some fresh basil. Use your imagination!