Blueberry buttermilk cake

Preheat the oven to 180 °C and prepare a baking tin (approx. 25 cm × 15 cm) lined with baking paper.

In a smaller bowl, mix the ingredients for the crumble: 90 g of flour, 50 g of sugar, 50 g of butter, and 5 g of cinnamon. Set the bowl aside for now.

In a larger bowl, pour the remaining 170 g of plain flour, 80 g of granulated sugar, and the baking powder. Add 1 egg, 150 ml of buttermilk, and 30 ml of rapeseed oil. Mix everything until smooth.