"One bowl" recipes are good because it's easier just to mix everything together! A couple of years ago I made a one bowl chocolate cake which was nice.
The gingerbread muffins were quite nice. I used applesauce instead of banana because I don't like it, but it still worked quite well. Also I used mixed spice rather than cloves and nutmeg separately. The recipe has molasses but treacle is more readily available in the UK and is similar, so it's a good substitute.
The topping is either a maple vanilla glaze or frosting (see recipe) but I decided instead to make some cream cheese/peanut butter frosting. I've used the cream cheese icing from the frosted white chocolate cake I sometimes make for Easter for ginger cakes before, and it's gone well with them. I also wanted to try out a peanut butter frosting I'd come across a while ago but thought it might not go so well with the ginger, since it's for banana cakes. In the end I made up the frosting without the peanut butter first (also followed the James Martin white chocolate cake recipe for the British measurements), put it on 7 of the muffins and then added peanut butter to the rest and put it on the remaining 5. Here's a picture:
