Preheat the oven to 325°F (165°C). Line an 8x8-inch baking pan with parchment paper, leaving a slight overhang for easy removal later.

Make the crust: In a medium bowl, combine the graham cracker crumbs and sugar. Stir in the melted butter until the mixture is well combined. Press the mixture evenly into the bottom of the prepared baking pan to form the crust.

Bake the crust: Place the pan in the preheated oven and bake for 8-10 minutes, or until lightly golden. Remove from the oven and set aside to cool.

Prepare the cheesecake filling: In a large mixing bowl, beat the softened cream cheese and granulated sugar together until smooth and creamy. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract and sour cream until fully combined.

Assemble the bars: Pour the cheesecake mixture over the cooled crust, spreading it evenly with a spatula.

Bake the cheesecake layer: Bake in the preheated oven for 35-40 minutes, or until the cheesecake is set and the edges are lightly golden. The center should be slightly jiggly but firm. Remove from the oven and allow to cool to room temperature.

Make the strawberry topping: In a small saucepan, combine the diced strawberries, sugar, and lemon juice. Cook over medium heat, stirring occasionally, for about 5-7 minutes, or until the strawberries have softened and released their juices, and the mixture has thickened slightly.

Cool and refrigerate: Let the strawberry topping cool to room temperature. Once the cheesecake bars are fully cooled, spread the strawberry mixture over the top. Refrigerate for at least 2-3 hours, or until fully chilled and set.

Slice and serve: Use the parchment paper to lift the bars out of the pan. Slice into squares and serve chilled.