Prepare the Crust: In a medium bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Mix until the crumbs are evenly moistened. Press the mixture firmly into the bottom of the prepared baking pan to form an even layer. Use the bottom of a measuring cup or a flat object to pack it tightly.

Make the Cheesecake Filling: Preheat your oven to 325°F (163°C) and line a 9x9-inch square baking pan with parchment paper, leaving some overhang for easy removal. In a large bowl, beat the room-temperature cream cheese until smooth and creamy. Add the granulated sugar and flour, and mix until well combined. Mix in the sour cream, heavy cream, vanilla extract, and salt until smooth. Add the eggs one at a time, mixing on low speed after each addition until just combined. Do not overmix.

Bake the Cheesecake: Pour the cheesecake filling over the crust, spreading it evenly with a spatula. Bake for 35-40 minutes, or until the center is set but still slightly jiggly. Turn off the oven, crack the oven door open, and let the cheesecake cool in the oven for 1 hour to prevent cracking. After 1 hour, remove the cheesecake from the oven and let it cool to room temperature. Then, refrigerate for at least 4 hours or overnight.

Make the Strawberry Jam: While the cheesecake is chilling, combine the diced strawberries, granulated sugar, and lemon juice in a medium saucepan. Cook over medium heat, stirring occasionally, until the strawberries break down and the mixture thickens to a jam-like consistency, about 15-20 minutes. Remove from heat and let the jam cool completely.

Assemble the Cheesecake Bars: Once the cheesecake is fully chilled, remove it from the pan using the parchment paper overhang and place it on a cutting board. Cut the cheesecake into rectangular bars. Using a sharp knife, carve out a small strip from the center of each bar, being careful not to go all the way through the cheesecake. Fill the carved out strip with the cooled strawberry jam. Melt the white chocolate in a microwave-safe bowl, microwaving in 30-second intervals and stirring until smooth. Drizzle the melted white chocolate over the top of each bar. Let the bars set for a few minutes to allow the white chocolate to harden. Serve the strawberry jam-filled cheesecake bars chilled and enjoy!