Line a loaf pan with baking parchment and preheat oven to 350F.

Sift together 1¼ cups flour, baking powder and salt and set aside. In the bowl of a stand mixer, cream together butter and sugars. Add the eggs one at a time and beat on high between additions until the mixture is light and creamy. Add in the vanilla and lemon zest and mix until incorporated.

Turn the mixer to half speed and add the flour in three additions, stopping between each addition to add half of the yogurt. Mix only until the flour has just been incorporated, being careful not to overmix. Turn off the mixer and remove the bowl. Sprinkle blueberries with a ½ teaspoon of flour, mixing to coat evenly, and then fold gently into the batter using a rubber spatula.

Bake until a toothpick comes out clean, approximately 40 to 50 minutes. (Note: depending on the size and water content of your blueberries, cooking times may be longer, up to 90 minutes).

Remove the cake from the oven and allow to cool while you make the icing.

Combine the cream cheese, icing sugar and sour cream in the bowl of a stand mixer and beat until thoroughly mixed. Refrigerate until you are ready to serve the cake, at which time you can spoon onto the top of the cooled cake. Garnish with additional fresh blueberries and slice to your desired thickness.