This Blueberry Buckle is an old-fashioned single layer cake, with a tender crumb, juicy sweet blueberries throughout, and a crisp streusel topping. Serve for dessert or breakfast!
Preheat oven to 350 degrees F. Grease an 8x8-inch pan.
For the topping: Using a fork, pastry blender, or your hands, combine all the ingredients until you have pea size crumbs. Place in the fridge while you make the cake batter.
For the cake: In a large bowl with an electric mixer, cream together the sugar, shortening, and butter until light and fluffy. Beat in the egg, lemon zest, and vanilla until combined, smooth, and fluffy.
In a separate bowl whisk together the flour, baking powder, and salt. Stir into the butter/shortening mixture, alternating with milk, mixing until just combined. (Batter will be thick.)
Fold in the blueberries, then spread batter evenly into the prepared pan.
Remove topping from the refrigerator and break it up into tiny pieces, then sprinkle evenly over the cake batter.
Transfer pan to the preheated oven and bake for 40-50 minutes or until a toothpick in the center comes out clean.
Cut into squares and enjoy!
NOTE: If using frozen berries, do not thaw them first to avoid discoloring the batter, and gently fold them in. You'll likely need to increase the baking time by 5-10 minutes. Watch the cake and tent with foil if the topping is over-browning.
VARIATIONS: Instructions included in the full article for doubling this recipe or converting into muffins.