Ingredients

Step by step

1. Preheat the oven to 180°C, fan 160°C, gas 4. Line 2 baking trays with baking paper.
2. Mix together the butter and sugars in a bowl with an electric mixer until fluffy. Gradually beat in the egg and the vanilla, then sift in the flour and salt. Bring together into a soft ball of dough (you may need to use your hands). Flatten into a round, wrap and chill for 1½-2 hours.
3. Roll out the dough on a floured surface to around 5mm thickness. If necessary, dust with more flour to prevent sticking. Use a 6cm round cutter to cut out the biscuits. You need 30 in total and may need to re-roll your scraps to get enough.
4. Use a smaller heart-shaped or round cutter or the end of a piping nozzle (2-3cm) to make a hole in the middle of half of the biscuits (these will be the tops). Transfer all the biscuits to the lined baking trays and put into the fridge for 15 minutes to firm up slightly.
5. Bake for 10-12 minutes, until light gold. Remove, sprinkle generously with the caster sugar and let cool on the trays.
6. When the biscuits are completely cool, spread about a teaspoon of the salted caramel on the bottom biscuits (leave a thin border so it doesn’t squish over the sides). Gently press on the top biscuits.