Mushroom toad-in-the-hole

I was planning to serve Continental toad-in-the-hole to friends for supper some months ago when I received a text from a guest reminding me his new girlfriend was a vegetarian. This sent me rifling through my fridge and there in the vegetable tray was a packet of mushrooms. I had already made the batter, so this recipe seemed the obvious solution! Make sure your mushroom mix is not too runny.