If your mix is too runny you will lose the light texture and have soggy muffins so be careful not to add too much. You should be able to leave a 'peak' when running a spoon through the mix. I used a silicon muffin tray and made 12 good sized muffins. I used dairy free spread but you could use butter if you're not dairy free. This is also gluten free if you use gf baking powder.
Forgot to say I also added a tsp of 'isabels gluten free baking fix' but could also use xanthan gum to make up for lack of gluten. - 15 Feb 2015