Himself found these huge portabella mushrooms at the store and decided we should have some. Nothing like dropping a chunk of change on mushrooms, right (impromptu price comparative here), only $2 per 'shroom.
They're not a bad size, even if they're extortionally priced. I forgot to add a comparison, but each one would cover my palm easily enough. I read online that the best way to do stuffed mushrooms is to remove the inner stalk and the brown gills, as these are bitter. I found that surprising, but dutifully did so and it really made a difference. The dish went from 'shroom to va-va-voom! Do yourselves a favor - use a spoon and scrape out those inner sections. It's a bit fiddly, but well worth it.
We sorta concocted our own filling, using frozen mixed veg that I warmed up to remove most of the moisture, then tossed with some herbs and spices for flavor. I squirted some pizza tomato sauce in the bottom of each cleaned mushroom, spooned in some veg, and topped it all with cheese and sliced cocktail tomatoes. Bake in a warm oven (about 350'F or 175'C) for about 20 minutes.