For the Argentine Alfajores dough
To prepare the Argentine alfajores cookies first mix the flour with the cornflour and baking powder.
Beat the eggs with the egg yolks, sugar, vanilla sugar and extract and the butter until light and fluffy.
Gradually mix in the flour mixture to make a smooth dough.
Wrap in clingfilm and chill for approx. 1 hour in the fridge.
For the Argentine Alfajores filling
Melt the butter in a high-sided not-stick pan.
Add the sugar, vanilla sugar and extract and a pinch of salt and let caramelize briefly.
Stir in the cream and milk, dissolving the caramel.
Simmer over a medium heat for approx. 45 minutes to form a thick cream, stirring at least every five minutes.
The dulce de leche is ready when it drips slowly from the spoon.
Heat the oven to 190°C (180°C in a fan oven, gas 5.
Divide the dough into 4-5 portions.
Leaving the remaining the dough in the fridge, roll out one portion at a time on a floured surface to a thickness of approx. 4 mm.
Cut out biscuits of 4-5 cm diameter and place them on baking trays lined with baking parchment, repeating this step until all the dough is used up.
Bake the full trays one at a time for approx. 10 minutes until the biscuits are pale yellow.
Remove from the oven and let the biscuits cool on a wire rack.
Spread 1/2 - 1 tbsp of the caramel cream on half the biscuits and place a second biscuit on top, pressing down so that a little of the cream comes out at the sides.
Roll the edges of the biscuits in coconut flakes.
Eat the Argentine alfajores cookies at once or pack into a box with a tightly-fitting lid and keep in the fridge.