Boterkoek (Dutch Butter Cake)

1. Preheat the oven to 180°C/350°F.
2. Cream the softened butter and sugar in a stand mixer until creamy, then add the flour and salt and knead by hand to a smooth dough. Divide into two pieces.
3. Line the base of a square or round cake tin (not a springform) with parchment and press the first half of the dough over the base with your fingers and a spoon.
4. Using a teaspoon, dot dulce de leche over the base, sprinkle with the chopped chocolate, and cover with the second half of the dough.
5. Brush the top with the beaten egg (don't worry if it isn't perfectly neat; it will be fine once baked).
6. Bake for about 30 minutes, until golden brown. It will still be wobbly, as butter cake only firms up as it cools.
7. Leave to cool completely, then cut into small pieces.

Tips from the ZestyPlate Kitchen

• Use good butter and plenty of it. It is the main flavour, and there is nowhere to hide a poor one.
• Take it out while it still wobbles. Boterkoek firms up as it cools, and overbaking leaves it dry.
• Press the dough flat with the back of a spoon and your fingers for a neat, level cake.
• Let it cool right through before you cut it, or it will crumble apart while warm.