Preheat the oven to 350º F. Prepare a 9 in baking pan with parchment paper, or spray with non-stick spray.
Cream together butter, 1 cup sugar and lemon zest until light and fluffy, about 2 minutes.
Beat in the egg and vanilla until the egg is fully incorporated.
In a separate bowl combine the blueberries with ¼ cup flour, tossing to fully coat.
Add remaining flour, baking powder and salt to the butter mixture. Stir in the yogurt until well combined.
Using a spatula fold in the blueberries.
Pour batter into prepared pan. It will be a little sticky. If you get your hand damp, you can use them to evenly spread out the dough. Sprinkle the remaining sugar over the top of the batter.
Bake for 35 minutes or until the cake starts to turn golden brown. A toothpick inserted should come out clean when done.
Let cool for at least 15 minutes before serving.
