Step 1

Preheat the oven to 350°F and line an 8 x 8 pan with parchment paper on all sides.

Step 2

First, make the crumb topping. Combine the brown sugar, white sugar, flour and salt in a bowl. Add the butter and use your fingers to rub the butter into the mixture until it clumps together and resembles wet sand. Set aside.

Step 3

Beat the butter and the sugar together in a stand mixer fit with the whisk attachment until light and fluffy. Scrape down the bowl and add the lemon zest and eggs. Mix well.

Step 4

Stir together the flour, baking powder and salt. Add half of the dry ingredients and beat until just combined. Add the buttermilk and mix. Add the rest of the dry ingredients and mix until just combined. Last, fold in the blueberries to distribute evenly.

Step 5

Spread the batter in an even layer in the prepared pan. Sprinkle with the crumb topping and bake for 40 to 50 minutes or until a knife inserted into the center comes out clean. Allow to cool before enjoying.