Preheat oven to 350°F (175°C). Line a square pan with parchment paper and lightly grease.
In a bowl, mix graham cracker crumbs, sugar, and melted butter. Press firmly into the pan to form the crust.
In a large bowl, beat cream cheese, sugar, sour cream, and vanilla until smooth.
Add eggs and mix gently until just combined.
Pour the cheesecake filling over the crust and smooth the top.
Bake for 25–35 minutes until the center is slightly jiggly.
Cool to room temperature, then refrigerate for 3–4 hours until fully set.
For the topping, cook strawberries, sugar, water, lemon juice, and cornstarch over medium heat until thickened. Let cool.
Spread the strawberry topping over the chilled cheesecake.
Melt white chocolate chips and drizzle over the bars.
Slice into squares and serve chilled. These Philadelphia Cheesecake Bars are best served cold.