Preheat your oven to 170°C / 150°C fan and line a cupcake tray with 12 cupcake cases.

Chop your blackberries into quarters and set them aside.

In a large mixing bowl, sieve the gluten-free flour, then add the xanthan gum, baking powder, and salt. Whisk until well combined.

In an electric stand mixer, add the unsalted butter and caster sugar. Beat on high speed for about 4 minutes until pale and fluffy.

Add one egg at a time, adding a tablespoon of the flour mixture with each egg, mixing on medium speed until fully combined.

Add in the Greek yogurt and vanilla extract. Mix until fully combined, then slowly add the remaining flour mixture on low speed until just incorporated.

Distribute the batter evenly into the cupcake cases, filling them about 3/4 full.

Push 8 pieces of chopped blackberry into each cupcake before baking.

Bake in the oven for about 20 minutes, or until a skewer inserted into the center comes out clean.

Leave the cupcakes to cool completely before frosting.

Add the remaining blackberries to a blender or food processor and blitz into a puree, then strain through a sieve.

In a mixing bowl, beat the unsalted butter until smooth. Gradually sift in icing sugar, mixing after each addition.

Once 3/4 of the icing sugar is mixed in, pour in the blackberry juice and mix again before adding the remaining icing sugar.

Pipe swirls of frosting onto each cooled cupcake and add an extra blackberry on top for decoration.