Blueberry Buttermilk Cake

Preheat the oven to 180 °C and prepare a baking dish (approx. 25 cm × 15 cm) by lining it with baking paper.

In a small bowl, mix all ingredients for the crumble topping and set the bowl aside for now.

Now prepare the batter: In a larger bowl, add 170 g all-purpose flour, 80 g granulated sugar, and baking powder, then add 1 egg, 150 ml buttermilk, and 30 ml rapeseed oil. Mix everything until smooth and pour the resulting batter into the lined dish.