Heat oven to 350. Spray a 9" springform pan w/ cooking spray. In medium bowl, combine blueberries, 1/2 cup sugar, 2 tbsp flour,, and 2 tbsp lemon zest. Toss to coat. pour into pan.
In lg bowl, cream butter a nd 1 cup sugar until fluffy. Beat in eggs, 1 at a time. Stir in vanilla and remaining zest.
In another bowl, stir together flour and baking powder. Beat flour mix into butter mix, alternately w/ milk. Pour batter over berries.. Bake about 1 hr, or until a toothpick inserted in center comes out cleaan. Sprinkle almonds on top of cake.upend cake onto a platter.