This is a gluten and dairy free version of my family's 'Jiffy tea cake' which is one of those basic cakes you can add almost anything to! It makes a smallish cake, so I usually double the mixture if making a whole cake, or just use the quantities below to make about 6 muffins.
I've given the quantities in 'cups' and by that I actually mean a tea cup that I've been using as my cooking measuring cup for the last 30 years! It doesn't really matter whether you use a metric or imperial cup as long as you use the same cup - though if you only have small eggs, I would perhaps use two. I also like to have a fairly thick batter, so I add more milk or flour as needed to get it to the right consistency - experiment to see what suits you and your oven best.