Follow these clear steps to create The BEST Philadelphia Cheesecake Bars effortlessly:

1. Preheat the Oven: Preheat your oven to 325°F (163°C). Line a 9×13-inch baking pan with parchment paper, allowing the parchment to hang over the edges for easy removal.
2. Prepare the Crust: In a mixing bowl, combine graham cracker crumbs, granulated sugar, and melted butter. Mix until the crumbs are well coated and resemble wet sand.
3. Press the Crust: Firmly press the graham cracker mixture into the bottom of the prepared baking pan, creating an even layer.
4. Bake the Crust: Place the crust in the preheated oven and bake for 10 minutes. Remove and let it cool slightly.
5. Make the Filling: In a large bowl, beat the softened cream cheese until smooth. Gradually add in the powdered sugar and continue mixing.
6. Add Eggs: Blend in the eggs, one at a time, making sure each is fully incorporated before adding the next. This helps to create a smooth texture.
7. Incorporate Other Ingredients: Mix in the vanilla extract, sour cream, and lemon juice (if using) until everything is combined and smooth.
8. Pour the Filling: Pour the cheesecake filling over the cooled graham cracker crust, spreading it evenly.
9. Bake the Cheesecake Bars: Bake in the oven for 30-35 minutes or until the edges are set and the center slightly jiggles.
10. Cool the Bars: Remove from the oven and let the bars cool in the pan on a wire rack. Once cool, refrigerate for at least 2-3 hours or overnight for optimal firmness.
11. Slice and Serve: When ready to serve, use the overhanging parchment paper to lift the bars out of the pan. Cut into squares and enjoy!