Prepare the Crust

1. Lightly grease a 9 by 13 inch glass baking dish with butter. In a bowl, combine graham cracker crumbs and sugar, pour in melted butter and stir until coated. Press mixture into the dish and chill for 20 minutes.

Bloom the Gelatin

1. In a heatproof bowl, pour cold water and sprinkle gelatin over it. Let sit for about 5 minutes.

Make the Yoghurt Filling

1. In a large bowl, beat cream cheese and powdered sugar until smooth, about 2 minutes. Add Greek yoghurt and mix until combined.

Incorporate Flavors

1. Add vanilla extract and lemon juice into the mixture, stirring gently until smooth.

Dissolve the Gelatin

1. Microwave bloomed gelatin for 10-15 seconds until dissolved. Stir until smooth and let cool slightly.

Combine Gelatin with Filling

1. Add 3 tablespoons of the filling to the gelatin, stirring until smooth. Slowly incorporate into the remaining filling.

Whip the Cream

1. In a chilled bowl, beat heavy cream on medium-high speed until stiff peaks form, about 2-3 minutes.

Fold in the Whipped Cream

1. Gently fold whipped cream into the yoghurt mixture until light and fluffy.

Assemble the Cake

1. Spread the yoghurt filling evenly over the chilled crust, cover, and refrigerate for at least 4 hours.

Make the Blueberry Topping

1. In a saucepan, combine blueberries, sugar, lemon juice, and water. Cook over medium heat for 5-7 minutes until berries burst.

Thicken the Blueberry Sauce

1. Dissolve cornstarch in cold water and add to the blueberries. Cook for about 2 minutes until sauce thickens.

Final Assembly

1. Check if yoghurt filling is set, spoon the blueberry sauce over it and scatter remaining blueberries and graham cracker crumbs. Refrigerate for an additional hour.

Serve the Cake

1. Lift each piece from the dish using a spatula and cut into 12 squares. Keep refrigerated until serving.