Start by mixing the butter and caster sugar together until well combined and creamy looking. This is best done in a stand mixer with the paddle attachment for 3-5 minutes.

Add the egg and vanilla extract, and mix until fully incorporated.

Add the plain flour and salt, and mix until combined and it starts to clump together.

Bring the mixture together into a smooth dough with your hands, and form into a rough disc shape. Wrap the dough in cling film and put it in the fridge to chill for 30 minutes.

Meanwhile, pre-heat your oven to 350°F, and line a few baking trays with baking paper.

Using a rolling pin, roll the dough out onto a floured surface to a thickness of 5mm. Keep turning the dough as you roll, to ensure it doesn't stick to the surface, and add more flour underneath as needed.

Cut out your biscuit shapes and place them onto the lined baking trays. You will need to re-roll out the dough to use it all up.

Bake the biscuits for 10-12 minutes, until just starting to go slightly golden around the edges. Leave to cool on the trays for at least 10 minutes before moving to cooling racks to cool fully.

Roll out your fondant, which you will need to do in batches, onto a surface dusted with icing sugar. Keep the fondant moving and add more icing sugar underneath if needed so it doesn't stick. Cut out the same shapes as your biscuits. Brush some edible glue in a very thin layer on the back of the fondant, or on the top of the biscuit, then place the fondant on top of the biscuit and smooth it out with your finger.

Set the biscuits back on the cooling rack for the fondant to firm up. You can add any additional decor at this point.

Store in an airtight container in a cool place for 3-4 days (although they can last up to a week), you can also freeze them.