Ingredients
125g cornflour
125g gluten free flour (wheat, buckwheat or rice flour)
1 tsp baking powder
1 tsp bicarbonate of soda
75g soft unsalted butter
50g icing sugar
1 egg yolk
50mls rum or brandy
½ tsp vanilla extract
For the filling
1/4tsp ground cinnamon
300g dulce de leche
Icing sugar for dusting
20g desiccated coconut
Method
Sift corn flour and flour into a large bowl, add a generous pinch of sea salt, the baking powder and bicarbonate of soda, and mix together.
In a separate bowl, beat the butter and the icing sugar until smooth and pale (use a freestanding mixer with a paddle attachment, if you have one), then beat in the egg yolk, rum and vanilla extract.
Scrape down the sides of the bowl and fold in the flour mixture until just combined – try not to overwork it.
Spoon the mixture onto a large piece of cling film, split into two balls with your hands and flatten into disks. Wrap in cling film and firm up in the fridge for at least one hour.
Heat the oven to 160C and line a couple of baking trays with greaseproof paper. Place each dough disc between two sheets of greaseproof paper and rollout to the thickness of pound coins. Use a 4cm cutter to cut out 30 biscuits, pushing the dough back together and re-rolling as needed. Transfer the biscuits to the lined trays.
Bake in batches on the middle shelf for 15-20 minutes, or until pale on top and golden underneath. Carefully transfer to a wire rack to cool while you bake the next batch.
In a bowl, mix together the ground cinnamon and a good pinch of sea salt into the dulce de leche, and beat until combined. (You can make dulce de leche by boiling a tin of condensed milk in a pan of water, being sure to keep the water topped up, for about two hours. Alternatively, you can buy tinned caramel by Carnation).
Turn over half the cooled biscuits and cover with dolce de leche mixture, then sandwich with another biscuit. Repeat with rest of the biscuits, roll the edges in the desiccated coconut and dust with icing sugar.