preheat to 350

spray 10" spring form pan with nonstick spray

stir together crumb ingredients until moistened, press in to bottom of pan

refrigerate pan, then stir together sour cream and sugar in bowl, cover and refrigerate as well

in large bowl, beat cream cheese until smooth

gradually cram in the sugar

beat in eggs one at a time

beat in egg whites, lemon zest and lemon juice, and vanilla, until well blended

pour into pan and bake until center jiggled slightly, about 55 to 60 min

let cool on wire rack for 15 min, then spin the topping onto the cake and spread

refrigerate at least 8 hours and up to 2 days

stir together corn starch and sugar to make the sauce, add blueberries and water and cook over medium heat for 4 min

after removing from heat stir in lemon juice, then transfer to bowl and refrigerate

dip thin knife in hot water between slices shaking off excess water, and make into 32 slices

serve topped with sauce