Isn't this thread great? So many good ideas.
Basically you can stuff a mushroom with anything. There are a few points where my vegan son and DDiL and my keto hubby cross over and mushrooms are one of those things.
Since hubby is so super low carbs (and I am low carb), mushrooms add a lot of options. Like with the big portabello caps, those are essentially "steaks" to the kids and a base for the hubby. You can do essentially a keto pizza on a big mushroom cap, kids are full vegan so no cheese for them. We do the big ones on the grill, they hold up fine.
Is funny, for awhile in his picky years the son refused to eat mushrooms and now yes they feature in his diet. Hubby always liked them fine but has become fascinated with them since turning keto. Now we when go on our walks we add looking mushrooms to the list of things. I've always been a fan and have foraged one variety (shaggy manes, very distinctive and prolific in the area I was in), and would buy different varieties in the grocery store, just like I try different types of apples. Here in the northwest and with our mixtures of cultures I've been very lucky to be exposed to things I think I would have very little access to in other parts of the country.