Creating No-Bake Flag Cheesecake Bars can be straightforward if you follow these simple steps:

1. Prepare the Pan: Line a 9×13-inch baking dish with parchment paper, leaving an overhang for easy removal later.
2. Make the Crust: In a bowl, mix graham cracker crumbs, melted butter, and granulated sugar. Press the mixture into the bottom of the prepared pan to form an even layer.
3. Prepare the Cheesecake Filling: In a large bowl, beat the softened cream cheese with an electric mixer. Gradually add powdered sugar and mix until smooth.
4. Add Whipping Cream: In a separate bowl, whip the heavy cream and vanilla extract until stiff peaks form. Gently fold the whipped cream into the cream cheese mixture until fully combined.
5. Divide the Filling: Separate the cheesecake filling into three bowls. Set aside one bowl for the white layer.
6. Make the Red Layer: In the second bowl, add the pureed strawberries and lemon juice. Mix until well incorporated.
7. Spread the Red Layer: Pour the red layer over the crust and spread evenly. Refrigerate for 30 minutes to set.
8. Make the Blue Layer: In the third bowl, add the pureed blueberries and lemon juice. Mix until well combined.
9. Spread the White Layer: Remove the pan from the refrigerator and spread the reserved white filling over the red layer. Smooth it out gently.
10. Spread the Blue Layer: Finally, pour the blue layer on top of the white filling and spread it evenly.
11. Chill: Cover the pan with plastic wrap and place it in the refrigerator for at least 4 hours, or overnight for the best results.
12. Slice and Serve: Once set, lift the cheesecake bars out of the pan using the parchment paper overhang. Cut into squares or rectangles for serving.

These steps will guide you in creating these stunning cheesecake bars effortlessly.