This sourdough blueberry buckle is a soft, tender vanilla cake made with sourdough discard and packed with juicy blueberries, topped with a buttery cinnamon streusel. It’s the perfect balance of sweet and slightly tangy, ideal for breakfast, brunch, or dessert.
Preheat oven to 350°F (175°C). Grease a 9x9-inch baking pan or line with parchment paper.
In a large bowl, cream the softened butter and granulated sugar together until light and fluffy. Add the eggs one at a time, mixing well after each addition. Stir in the sourdough discard and milk until fully combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined. Do not overmix. Gently fold in the blueberries.
Spread the batter evenly into the prepared baking pan.
In a small bowl, combine the brown sugar, flour, and cinnamon for the streusel.
Cut in the cold butter using a fork or pastry cutter until the mixture forms coarse crumbs. Sprinkle the streusel evenly over the batter.
Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean.
Allow the buckle to cool in the pan for at least 20 minutes before slicing and serving.