cups = american measuring cups and are level measures.
In one bow sift/add together:
2cups of plain flour
3tsp (level) baking powder
1/4 - 1/2 cup of caster sugar (depends how sweet you like them)
zest of 2 medium sized oranges
1/4 tsp of salt
In another bowl mix together
1 cup of orange juice (squeezed from the two oranges - if not enough make up rest with water)
1/4 cup of oil or butter
Makes enough for a standard 12 cup muffin tin.
Add the wet ingredients to the dry and mix until the flour is just incorporated. A lumpy batter makes lighter muffins. Pop in muffins pans (well greased or use papers or silicon cups), and bake for approximately 20 mins at 200 c (I tend to do mine for 16 mins on 160 but I have a fan oven that is viciously hot.. plus the silcon means heat is distributed more eveningly so cooks a bit quicker too).
Same recipe for lemon muffins, which actually I think taste better. (although Saville Oranges, when available in January, are good for this recipe). Although a few drops of orange essential oil will certainly help to add to the orangy flavour, (must be 100%, preferably organic, orange essential oil). Orange icing helps the flavour along too - 1/2 cup of icing sugar to 1-2tsp of orange juice and then drizzled over the muffins when slightly warm (too hot and the icing will just soak into the muffins)
P.S Vegans the egg can be left out just add 1/2 tsp of bicarb instead.