Position a rack in the middle of an oven and preheat to 350 F. Butter a 2 ½ quart nonstick or regular Bundt pan (10-inches in diameter and 3 inches deep).
In a medium bowl, sift together the flour, baking powder and salt. In a large bowl, using an electric mixer set on medium-high speed, beat the butter until light. Add the sugar and beat until blended. Add the eggs, one at a time, beating well after each addition. Beat in the vanilla extract and lemon zest and then the sour cream. Reduce the speed to low and, dividing the flour mixture into 3 batches, beat the flour mixture into the butter mixture alternately with the milk, beginning and ending with the flour mixture. Beat just until combined. The batter will be very thick.
Spoon half of the batter into the prepared pan. Sprinkle with 1 cup of the blueberries. Gently press the berries into the batter. poon the remaining batter over the berries and then sprinkle the remaining berries over the top, again pressing them gently into the batter.
Bake until a toothpick inserted near the center comes out clean, about 1 hour. Transfer to a rack and let cool in the pan for 10 minutes. Invert onto the rack and let cool completely.
Transfer the cake to a plate. Drizzle the icing evenly over the top, allowing it to run over the sides slightly. Serve immediately, or cover with a cake dome and store at room temperature for up to 1 day.