Preheat the oven to 325°F (165°C).
In a mixing bowl, combine graham cracker crumbs, melted butter, and ¼ cup granulated sugar. Mix until well combined.
Press the crumb mixture firmly into the bottom of a 9-inch springform pan. Bake for 10 minutes, then set aside to cool.
In a separate large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy.
Gradually add 1 cup of granulated sugar to the cream cheese, mixing well.
Add the eggs one at a time, mixing well after each addition. Then, mix in the vanilla extract, mashed bananas, sour cream, ground cinnamon, and salt until evenly combined.
Pour the cheesecake batter over the cooled graham cracker crust in the springform pan, smoothing the top with a spatula.
Bake the cheesecake in the preheated oven for about 50-60 minutes, or until the center is set but still slightly jiggly.
Turn off the oven, crack the door open, and allow the cheesecake to cool inside for about 1 hour.
Remove the cheesecake from the oven and let it cool to room temperature. Then, refrigerate for at least 4 hours or overnight before serving.
Before serving, garnish with extra banana slices if desired.