(from the lovely Zucker, Zimt und Liebe by Virginia Horstmann)
200g softened butter
200g brown sugar
110g caster sugar
1/2 teaspoon baking soda
a large pinch of cinnamon
a pinch of salt
4-6 tablespoons cinnamon sugar
Preheat the oven to 175°C and grease a 20x30 cm baking tin with butter and line with parchment paper (I used my 23x18 brownie tin and another small baking tin).
In a large bowl, beat butter and sugar with an electric hand mixer until creamy. Add baking soda, cinnamon and salt. Then, add the eggs and after that, the flour. Beat until well combined. You will end up with a rather thick dough.
Spread the dough into your baking tin with a ladle and bake for about half an hour. Don't overbake, it's ok if it's a little soft in the middle still. Sprinkle with cinnamon sugar immediately.
Let cool down, cut into squares.