Step 1

Grease and flour a 9 inch spring form pan and line the bottom with parchment paper if you like, for easier release. Preheat oven to 325 degrees F.

Step 2

Sift together the flour, baking soda and baking powder and set aside.

Step 3

Cream together the butter and sugar well. Add the vanilla extract and lemon zest.

Step 4

Beat in the eggs, one at a time, beating well after each addition.

Step 5

Fold in the dry ingredients alternately with the sour cream. I do this on low speed in my mixer.

Step 6

Always begin and end with the dry ingredients when adding them alternately. I generally add the dry ingredients in 3 portions and the sour cream in 2 portions.

Step 7

With the final portion of dry ingredients, fold in the partridgeberries by hand. Spread the batter evenly into the prepared spring form pan.

Step 8

Bake for approximately 1 hour. Deeper pans may take an additional 10 minutes or more. When a wooden toothpick inserted into the center of the cake comes out clean it is done.

Step 9

Cool the cake in the pan for about 15 minutes before removing the sides of the spring form pan and cooling the cake completely on a wire rack. If serving for brunch, I like to serve it warm, after at least a half hour out of the oven.

Step 10

Just mix the ingredients together until smooth. You want it very thick but pourable.

Step 11

Add a little extra icing sugar if you think it is too thin.