Preheat oven to 325ºF (160ºC) conventional. Line the bottom of a 9-inch springform pan with parchment paper.
Process crackers and sugar in a food processor until fine and sandy. Add melted butter and blend until combined.
Press cookie crumb mixture into the bottom and up the sides of the springform pan. Bake for 10 minutes. Cool before filling.
In a bowl, mix blueberries, sugar, flour, and lemon juice until coated. Set aside.
For the crumble, combine flour and brown sugar in a bowl. Pour melted butter over and mix with a fork until crumbly.
Beat cream cheese with sugar on low speed for 1 minute. Scrape bowl and mix 30 seconds more.
Mix sour cream with cornstarch until smooth. Add vanilla extract and blend into cream cheese mixture on low speed.
Add eggs two at a time, mixing on low speed until combined. Scrape bowl and mix once more.
Pour cheesecake batter over cooled crust. Evenly distribute blueberry mixture over batter, then sprinkle crumble on top.
Place springform pan in a larger 12-inch pan, then place in a larger roasting pan. Add hot water to the roasting pan for a water bath.
Bake cheesecake for 1 hour and 20-30 minutes. The center should be slightly wobbly when done.
Turn off oven and leave door slightly open. Let cheesecake cool in oven for 1 hour.
Remove from oven and water bath, then cool on a wire rack for 1 hour until room temperature.
Refrigerate cheesecake for at least 6 hours or preferably overnight before serving.