Preheat oven to 350˚F. 

Grease and flour two 8-inch round cake pans.

Sift the flour, baking powder and salt into a medium bowl. Reserve.

In a large mixing bowl, beat the butter until smooth. Add 2 cups sugar and mix on high speed until light and fluffy.  Add the eggs one at a time, scraping the sides and bottom of the bowl after each addition. Add the vanilla and lemon zest and mix thoroughly. Add half the sour cream and continue mixing. Add half the flour mixture. Repeat, mixing until just combined. Do not overmix.

Pour equal amounts of the cake batter into the pans. Bake for 30-40 minutes or until the cakes spring back to the touch and are slightly brown along the edges. When done, remove cakes from pans and transfer to a wire cooling rack.  Allow cakes to cool completely.

For the sweet cream filling, combine sour cream, sifted sugar, and vanilla extract in medium mixing bowl. Stir until sugar dissolves.  Place cream in a large mixing bowl and beat with an electric mixer on high speed until soft peaks form, about 1 minute. Do not overbeat. Add the sour cream mixture to the whipped cream, and fold in the whipped cream until just combined.

To serve, place one layer of the cake onto a serving dish.  Spread half the cream mixture on top and sprinkle with a single layer of berries.  Place the remaining layer of cake on top of the layer of filling and berries. Cover the top of the cake with the remaining cream mixture and berries. Refrigerate until ready to serve.  For best results, cut with a serrated knife.