I've discovered Almond meal to be a great replacement for flour and I've also been replacing butter/marg with olive oil.
I tried some Banana Muffins on the weekend and they were delicious.
I did make some amendments to the original recipe and next time I reckon I'll tweak it some more by replacing the 1 cup of SR Flour with wholemeal flour and taking the sugar out altogether and perhaps adding a bit more golden syrup/honey to compensate.
The original recipe can be found here. And below is my version. I've made a note on my recipe as to what changes I made from the original. No need for a mixer either, I just used the whisk to gently mix all the ingredients together...simple and quick!
I'd love to hear of how you have altered recipes to be a healthier option.