If you use an egg or a brand egg-replacer you'll need to add a 1/4 tsp xanthan gum to the dry ingredients as my egg replacer has it included
Preheat the oven to gas 4 / 180C / 350°F and line a 12 hole cupcake tin
Mix the dry ingredients together
Add the zest, oil, agave, orange juice, egg replacer and vanilla
Beat smooth then let rest a couple of minutes
Spoon evenly into the cupcake cases and bake for 20 - 25 minutes. They'll rise quite a lot then settle
When nicely golden and done, remove and cool on a wire rack
Cream the powdered sugar and butter together and add the vanilla. Add enough orange juice to form a medium consistency frosting
Pipe it in a swirl around the cupcake tops when cooled and finish with some extra grated orange zest
These can be frozen. Once frozen wrap individually. Remove wrapping before defrosting to keep the frosting shape
