Preheat oven to 180 C or 350 F. Line 12 cup cake tins with paper liners or 24 mini cupcakes.
Combine the flour,salt, xanthan gum and baking powder in a mixing bowl. Sift into another bowl to make sure all the dry ingredients are combined.
In a separate bowl beat the butter with the sugar until it's light and fluffy. Gradually add the eggs little by little to make a mixture which looks like mayonnaise. Add the vanilla essence.
Using a large metal spoon add the dry ingredients to the butter and egg mixture. Mix gently to combine. Add the milk or creme fraiche at the end and mix through until just combined. Try not to overmix as this will make the cake rubbery.
Fill the prepared muffin tins with cake mixture until just half full. Don't be tempted to overfill them as this is likely to mean collapsed cupcakes. These will still taste great, but they are little sad to look at. Of course, the icing will hide a multitude of sins, so don't worry if this happens. Belive it or not, it happens to me all the time.
Bake the cupcakes for 8-10 minutes for mini cupcakes or 12-15 ,minutes for standard cupcakes. Leave to cool completely before icing.
Great cakes start off with butter and eggs which are at room temperature. The butter should be easy to squash with your fingers, but not melted. If you can plan this in advance and leave your butter out overnight, you will see a dramatic improvement in your baking.
I've been using my Thermomix to make this cake with great success. If you've got a Thermomix you can pretty much put everything in in one go and blitz on speed 6 for about 20 seconds. Scrape down the bowl and blitz again for a further 10 seconds if required. That means making this cake in less then 1 minute and yes it's pretty spectacular. Check out the Thermomix UK, cooking with Janie to see what else you can do.