Preheat the oven to 350°F (175°C) and line an 8x8 inch baking dish with parchment paper.

In a mixing bowl, combine the graham cracker crumbs and melted butter, then press the mixture firmly into the bottom of the prepared baking dish to form the crust.

In a large bowl, beat the softened cream cheese and sugar together until smooth and creamy.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

Gently fold in the diced peaches and cinnamon, if using, until evenly distributed.

Pour the cheesecake mixture over the crust in the baking dish and spread it evenly.

Bake in the preheated oven for about 25 minutes, or until the edges are set and the center is slightly jiggly.

Allow to cool at room temperature for 10 minutes, then refrigerate for at least 2 hours before cutting into bars.