Prepare the Crust:
Preheat oven to 325°F (160°C).
In a bowl, mix graham cracker crumbs, sugar, and melted butter until combined.
Press the mixture firmly into the bottom of a 9-inch springform pan.
Bake for 8 minutes, then let it cool while you prepare the filling.
Make the Cheesecake Filling:
In a large bowl, beat cream cheese and sugar until smooth.
Add eggs, one at a time, beating until just combined.
Mix in vanilla extract, drained crushed pineapple, and flour until evenly blended.
Pour the filling over the cooled crust and spread evenly.
Bake the Cheesecake:
Bake for 50-55 minutes, until the center is slightly jiggly but set.
Turn off the oven, crack the door open slightly, and let the cheesecake cool inside for 1 hour (this prevents cracking).
Transfer to the refrigerator and chill for at least 4 hours or overnight.
Prepare the Pineapple Topping:
In a saucepan, combine crushed pineapple, sugar, cornstarch, and lemon juice.
Cook over medium heat, stirring constantly, until the mixture thickens (about 3-5 minutes).
Let it cool, then spread over the chilled cheesecake before serving.