In a bowl of a standing mixer fitted with the paddle attachment, or using a handheld electric mixer, whip the cream cheese and sugar together on high until light and fluffy, about 2 minutes.
Add the vanilla extract and Greek yogurt, and whip again for another minute or two.
In another bowl using a handheld electric mixer, or in a clean mixing bowl using your stand mixer fitted with the whisk attachment, whip the heavy cream on high until stiff peaks form. Fold the whipping cream into the cream cheese mixture using a spatula, until combined.
Remove the pan from the freezer or fridge, and empty the filling into the crust, smoothing it all out with a spatula. Place the entire pan into the fridge for 4-6 hours until firm.
Using the overhang of the parchment paper to remove the bars from the pan onto a cutting board, and using a very sharp knife, cut the bars into even squares (9 or 16). Clean the knife before each cut.
Top with blackberry sauce (recipe below) or your desired topping. Serve