I have been making muffins quite a bit mostly because I've developed a formula that seems to work be they savoury or sweet. They rise well and have a great texture. I've done cheese and marmite ones, chocolate ones, various different fruits, ham and cheese and several others.
1/4 cup of liquid fat (olive oil, veg oil, melted butter)
1/4 liquid ( I mostly use yogurt or double cream but I have used fruit juice and that worked to)
1 cup flour mix
2 tsp baking powder
1/2 tsp salt (for savoury)
1- 1 1/2 cups of flavouring that includes sugar for sweet versions.
Pick a flour mix to suit your muffin flavour, make sure there is some bulking flour and some starch but most mixes seem to work. I've used Dove Farm plain flour mix, mixed my own rice based flour, used half Dove Farm, half gram flour for cheese ones and so on.
Pre heat the oven to 200 C and line a muffin tin with cake cases.
Prep your flavouring first up to 1 1/2 cups worth, ie grate cheese, chop fruit etc. If making sweet ones I use at most 1/3 cup of sugar and many sweet fruits we find work without sugar which is great for kiddy lunchboxes.
Beat the eggs and oil together than add the liquid and mix well.
Sieve in the flour mix and baking powder, plus salt if using, into the egg mix and fold in well.
Add flavours including sugar for sweet ones and mix well.
Spoon into cases, I use 9 for large muffins, 12 for cupcake size.
Cook at 200 C for 20mins for muffins and 15 for cupcakes.