Start by making the raspberry jam since it will need time to cool before you assemble the bars. Combine the frozen raspberries with sugar, cornstarch and lemon juice. Stir to coat and heat over a medium flame for 5 minutes, stirring occasionally. The mixture will start to bubble. Stir for an additional 3 to 5 minutes until the mixture is thick and glossy like jam.
Pour it into a dish and refrigerate.
In a medium bowl, mix together the cream cheese, sugar, vanilla and egg with a hand mixer or by hand until it's smooth and creamy.
Preheat the oven to 350F and line a 9x13 pan with parchment paper. Leave some paper overhanging on the edges so you can lift the bars out later.
Combine the brown sugar, sugar, flour, salt and baking powder in a large bowl. Mix with your hands or your fork, breaking up any sugar lumps as you go, Add in the melted butter and use your hands to form moist crumbs.
Press ⅔ of the crumble mixture into the bottom of the 9x13 pan.
Spread the cream cheese over the crust.
Spoon the cooled raspberry filling over the cream cheese, gently as to not mix it in.
Gently toss the remaining crumble over the jam to cover.
Bake for 35 to 40 minutes.
Allow the bars to cool for 20 minutes before transferring them to the fridge for at least 2 hours.
Lift the bars out and slice into 16 squares.
