Chop the chocolate coating the day before. Bring the cream to the boil in a saucepan and remove from the heat. Melt the couverture and 50 g butter while stirring. Stir in the advocaat. Fill chocolate egg liqueur cream into a bowl and let it cool down.
Cover and leave to set overnight in the refrigerator.
Peel, wash and finely grate the carrots. Cream 225 g butter, sugar, vanilla sugar and eggs. Mix flour, baking soda, baking powder and 1⁄4 tsp. cinnamon. Gradually stir into the butter and egg mixture.
Fold in grated carrots and oat flakes. Let the dough rest in the refrigerator for at least 1 hour.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line two baking trays with baking paper. Using a teaspoon, place approx. 16 piles of dough of approx. 4 cm Ø at a large distance (the cookies run apart!) on each baking tray.
Bake in a hot oven for 12-15 minutes one after the other. Remove from the oven and leave to cool on the tray for about 10 minutes. Then let it cool down completely on a cake rack. Process the remaining dough in the same way. Bake a total of about 64 cookies.
The next day, spread the underside of approx. 32 cookies with 1 teaspoon of advocaat cream each and place 1 uncoated cookie on each. Press on lightly.