1. Preheat your oven to 350°F (175°C) and line a 9×9-inch baking pan with parchment paper, leaving an overhang for easy removal.
2. In a medium bowl, mix the graham cracker crumbs, granulated sugar, and melted butter until well combined. Press the mixture firmly into the bottom of the prepared pan to form an even layer.
3. Bake the crust for 8-10 minutes until lightly golden. Remove from the oven and let it cool slightly while you prepare the cheesecake filling.
4. In a large bowl, beat the softened cream cheese until smooth and creamy. Gradually add in the powdered sugar and vanilla extract, continuing to beat until fully combined.
5. Add the eggs one at a time, beating on low speed until just incorporated. Be careful not to overmix to avoid incorporating too much air.
6. Pour the cream cheese mixture over the cooled crust, spreading it evenly. Bake for 25-30 minutes, or until the center is set but still slightly jiggly.
7. While the cheesecake is baking, combine the sliced strawberries, strawberry jam, and lemon juice in a small saucepan over medium heat. Cook, stirring occasionally, until the mixture thickens slightly, about 5-7 minutes. Set aside to cool.
8. Once the cheesecake is baked, allow it to cool to room temperature before spreading the strawberry mixture evenly over the top.
9. Refrigerate for at least 2 hours, or until fully set. Use the parchment overhang to lift the bars from the pan and slice into squares.

Remember, patience is key here — letting the bars chill completely will ensure clean slices and the most satisfying texture. This is a trick my grandmother taught me, emphasizing that a little waiting can lead to the best results.