Mushrooms are often used as a meat replacer in recipes, since they have a similar protein structure to meat, and a deep earthy flavor. Isabelle's suggestion of smoked tofu would probably work well. Similar texture at least, and proteiny. Depending on the recipe, you could just up the amount of other veggies.
I have the problem that I love mushrooms and my bf hates them, so unless they're cut up small, I have to cook them on the side and add them back into my dinner