Pre-heat the oven to 175℃ (350℉). Grease and line an 18cm (7") springform pan.
Heat the butter in a pan until about half of it has melted.
Remove from the heat, and continue to stir until all of the butter has melted.
Add the eggs and sugar and quickly whisk just until everything is combined.
Add the other ingredients and whisk quickly, just until everything is combined.
Pour into the prepared pan and bake for around 15 minutes. Please read my main post about how to bake a kladdkaka, and when to know it's ready.
Sprinkle with a good helping of icing sugar. Serve warm as it is, or allow to cool. Top with ice-cream or cream, if you fancy.