Preheat your oven to 400°F (200°C). Slice fresh peaches and toss them with brown sugar, cinnamon, and lemon juice. Spread the peach mixture on a baking sheet lined with parchment paper, roasting for 20–25 minutes until soft and caramelized, then allow to cool.

In a mixing bowl, combine all-purpose flour, oats, brown sugar, and cubed butter. Mix until crumbly and well combined. Spread the streusel mixture evenly on a baking sheet and bake at 350°F (175°C) for about 15 minutes, or until golden brown.

In a separate bowl, combine graham cracker crumbs, granulated sugar, and melted butter until moistened. Firmly press this mixture into the bottom of a greased 9-inch springform pan to form the crust. Bake at 325°F (160°C) for 10 minutes.

In a large mixing bowl, beat cream cheese and granulated sugar together until smooth. Gradually add eggs, one at a time, and stir in vanilla extract.

Pour half of the cheesecake filling over the cooled crust. Layer the roasted peaches and half of the streusel, then spoon the remaining cheesecake filling over. Bake at 325°F (160°C) for 50–60 minutes.

Once baked, turn off the oven and let the cheesecake cool inside for about an hour. Refrigerate for at least 4 hours, or overnight to firm up.

While the cheesecake cools, roast any remaining sliced peaches with brown sugar at 400°F (200°C) for 10–15 minutes until tender. Cool before layering them atop the cheesecake.