Preheat your oven to 350°F (175°C).
Mix graham cracker crumbs, sugar, and melted butter in a medium bowl until evenly moistened.
Press the mixture into the bottom of a 9-inch springform pan and bake for 10 minutes.
Set aside to cool.

Reduce the oven temperature to 325°F (163°C).
In a large bowl, beat cream cheese and sugar until smooth.
Add eggs one at a time, beating well after each addition.
Stir in sour cream, mashed bananas, and vanilla extract until just combined.
Pour the filling over the cooled crust.

Bake for 50–60 minutes, until the center is set but still slightly jiggly.
Turn off the oven, crack the door, and let the cheesecake cool inside for 1 hour.
Transfer to the fridge and chill at least 4 hours or overnight.

In a saucepan over medium heat, combine strawberries, sugar, and lemon juice.
Cook for 5 minutes until juices are released.
Mix cornstarch with water and stir into strawberries.
Cook for 2–3 more minutes until thickened. Let cool completely.

Remove chilled cheesecake from the pan.
Spoon cooled strawberry topping over cheesecake.
Garnish with extra sliced strawberries if desired.