Great question — answering as the UphillTech team:
First, the good news: the right flours can indeed make a difference. The optimal one I have found for a light texture is corn starch. As you say that you can't have that one either, the second best is non-glutinous rice flour. Try to find a mix with a high proportion of it. Flours you should avoid for light muffins include: dark flours, e.g. from teff or buckwheat whole grain flours large-particle-size flours nut flours Sadly, the third one is not something you can find written on the packaging - so if you want to develop a mix on your own, you will have to buy flours from different producers and see which one is ground more finely, then stick to that provider. Also, when developing a mix,...
Full answer by rumtscho: https://cooking.stackexchange.com/a/110100 (CC BY-SA 4.0).
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