In a medium bowl, combine the melted butter and crushed graham crackers. Stir until the mixture develops a wet sand texture. Cover the bottom of a greased 9x13-inch baking pan with the graham cracker mixture and spread evenly. Chill.

In a large bowl, combine the cream cheese, eggs, vanilla, and sugar. Stir until the mixture is smooth.

Spread half of the cheesecake batter into the chilled baking pan, smoothing the top, and freeze.

Preheat the oven to 325°F (160°C). Add the pumpkin puree to the remaining cheesecake batter and stir until incorporated. Spoon the pumpkin cheesecake mixture over the frozen cheesecake mixture and spread evenly.

Bake for 30 minutes.

While the cheesecake bakes, make the crumble topping. In a medium bowl, combine butter, flour, brown sugar, and cinnamon. Use a fork or your hands to mix until crumbly.

After 30 minutes, remove the cheesecake from the oven and sprinkle the crumble topping evenly over the top. Return to the oven and bake for an additional 15 minutes.

Remove from the oven and let cool completely. Refrigerate for at least 4 hours or overnight before cutting into squares and serving.