Step 2

Add the flour, cornstarch, cocoa, baking soda and baking powder. Mix until a dough forms. Wrap in plastic wrap and chill for at least 30 minutes or overnight.

Step 3

Preheat the oven to 200°C. Line two baking sheets with parchment paper.

Step 4

Divide the dough into two portions; keep one refrigerated while you work with the other. Roll out to about 2mm thick and cut into 5–6cm rounds. Bake one tray at a time for 8–10 minutes. Let cool completely.

Step 5

Match cookies in pairs by size. Spread about 1 tsp dulce de leche onto the flat side of one cookie and sandwich with a matching cookie.

Step 6

Chop the chocolate and melt it with the butter and orange zest over low heat, stirring until smooth.

Step 7

Dip each sandwich cookie into the melted chocolate and place on parchment paper to set.