Canned mushrooms are rubbery and gross. I hope we can all agree on that. Mushrooms as they are do not have enough flavor to stand up to the strong flavors of a pizza. I always wondered why the hell people even bothered to put them on their pie. Here's what I have started doing. First, my pizza sauce is either thinly sliced garden grown tomatoes or canned diced tomatoes that I have seasoned to my liking. After applying the sauce to my pizza and before the cheese, I add dried portabellas, just as they are without reconstituting them. There is enough moisture from the "sauce" to just get them softened a bit while the pizza bakes. The mushrooms have a "bite" to their texture and the earthy, concentrated flavor actually stands up and asserts itself.