Preheat oven to 350 degrees.
Cream the butter and sugar together, and then add in the lemon peel and egg.
In a separate mixing bowl, combine dry ingredients. Mix to incorporate.
Pour dry ingredients into wet ingredients a little at a time, alternating with sour cream and mixing as you go.
Spray a 9-10 inch spring-form pan with non-stick cooking spray and add the cake mixture to the pan, pushing it down along the bottom of the pan and about an inch up the sides.
Next, mix ingredients for the blueberry filling in a medium-sized mixing bowl. Gently pour and press onto the crust.
Bake for 45-55 minutes, until the top of the cake is lightly golden.
Remove from oven and cool on a wire rack. Run a knife along the edges of the cake to make sure it doesn’t stick, and then release the spring to remove the cake.
Mix the glaze in a small bowl, stirring the milk into the powdered sugar until a nice smooth consistency is reached. Spoon glaze over the cake.
Serve and enjoy.