A loving gingerbread house (with no ginger)

Mix the butter with the flour, the potato starch and cocoa.Add the sugar, the yolks and the lemon zest.Mix it until well combined (I used my hands) and let it rest one hour in the fridge.Preheat the oven to 180°C/356°F.Roll it out and cut the parts of the house gently offered by Lisa with a knife and a pizza cutter.Place them on oven trays (2) covered with parchment paper.Bake for 15 min.Let it cool and build the house using a mixture of egg white and icing sugar.Buon appetito and Merry Christmas!