Blueberry Buckle Coffee Cake is the ultimate brunch treat: light, fluffy, perfectly moist crumb, studded with tart/sweet beautiful blueberries. The cinnamon crumb topping is really the icing, er, crumb on the cake! As a self-proclaimed coffee cake snob, this one is by far my all-time fave! It will leave you speechless.
Preheat the oven to 375℉. Spray an 8x8 square baking pan with nonstick spray, and line with parchment paper for easy removal. Set aside.
Combine your dry ingredients. in a medium bowl, whisk together the flour, baking powder, salt, and lemon zest. Set aside.
Add the softened butter to the bowl of a stand mixer. Cream the butter on medium-high speed for 1-2 minutes, then add the sugar and continue to cream the butter and sugar together for another 2 minutes, or until light and fluffy, scraping down the sides as needed. Add the vanilla and Greek yogurt and beat until combined. Lower the speed and add the milk, gradually, until the mixture comes together. It might look like it has slightly curdled, and that's ok!
On low speed, gradually add the dry ingredients to the wet, mixing until just combined. Be careful not to overmix!
In a separate bowl, toss the blueberries with the tablespoon of flour until lightly coated. Gently fold the blueberries into the batter. Transfer the batter to the prepared pan, smoothing out the top with a rubber spatula until even. Batter will be thick.
In a small bowl, make the crumble topping. Whisk together the melted butter, granulated sugar, brown sugar, cinnamon, and pinch of salt until smooth. Add the flour and whisk together until mixture forms something resembling wet sand. Using your fingertips, crumble the topping evenly over the surface of the batter. Bake for 40-45 minutes, or until the crumble topping is golden brown, the center of the cake is set, and a toothpick inserted into the center of the cake comes out clean.
Let the cake cool completely, then remove from pan, and cut into 9 squares. Finish with a generous dusting of powdered sugar, and enjoy!