To make the crust, break up the graham crackers in a food processor into a coarse crumble. Mix it together with the brown sugar and melted butter in a bowl until combined.

Add the filling into the bottom of a 9 inch (or 7 inch if you prefer a taller cake) springform pan. Spread it to cover the bottom of the pan and slightly up the sides.

Now place this crust in the freezer to set while you make the filling.

For the filling, start by placing blueberries and blackberries in a small pan or pot on medium heat with 1 tsp granulated sugar and 1 tbsp water. Reduce for 3-5 minutes, occasionally lightly smashing the berries with a spatula. Set aside and let cool.

Pour the heavy cream into a bowl and use an electric mixer until stiff peaks. In a separate bowl, combine the reduced berries, skyr yogurt, powdered sugar, and vanilla yogurt. Slowly/carefully incorporate this mixture into the whipped heavy cream until combined.

Pour the filling into the crust in the springform pan, cover with plastic wrap, and place in the fridge for at least 6 hours or overnight (or alternatively in the freezer for 3 hours).

Once ready to serve, use a knife or spatula to separate the filling/crust from the pan and carefully open the springform.