Step 1: Preheat your oven to 325°F (160°C).
Step 2: In a medium mixing bowl, combine the graham cracker crumbs, melted unsalted butter, and packed light brown sugar. Stir until the mixture resembles wet sand. Add a pinch of salt if desired.
Step 3: Press the graham cracker mixture into the bottom of a 9x9-inch baking pan.
Step 4: Bake the crust for about 10 minutes or until lightly golden. Let it cool slightly.
Step 5: In a large mixing bowl, beat the softened cream cheese until creamy. Gradually add the granulated sugar, cornstarch, and vanilla extract. Mix in the egg until just incorporated.
Step 6: Gently fold in the melted peanut butter, leaving some streaks.
Step 7: Pour the cheesecake filling over the cooled crust and create swirls with remaining melted peanut butter.
Step 8: Bake for about 25-30 minutes, until the center is set but still slightly jiggly.
Step 9: Let it cool to room temperature, then refrigerate for at least 4 hours.
Step 10: Slice into squares and serve.
