Steps

1. Heat the chocolate and unsalted butter (for the batter) to 50℃. Set aside.

2. In a bowl, mix egg yolk, egg white and sugar (for the batter) on low speed until the sugar melts.

3. Add in the mixture from Step 1 and cake flour (for the batter), continue mixing.

4. Chill in fridge for about 4 hours.

5. In a separate bowl, mix sugar and unsalted butter (for the cookie base) until light and fluffy. Add flour and continue mixing on low speed.

6. Preheat oven to 170℃. Pour the mixture from Step 5 into a heart-shaped mould, bake for 12 minutes.

7. Remove baking mould from the oven and let cool. Pour in mixture from Step 4 and bake in the oven at 140℃ for 12 minutes. Sprinkle with icing sugar.