Arrange a layer of cake cubes on the bottom of a trifle bowl.
Pour the raspberry sugar mix over the cake.
Spread half of the pudding over it.
Arrange the second layer of cake on top of the pudding.
Line raspberries around the sides of the bowl over the cake layer.
Then fill the circle with a layer of raspberries.
Spread the remaining pudding over and sprinkle 3 tablespoons of pistachios in an even layer, starting with the edges of the bowl so you can see them from the outside of the bowl.
Arrange the third layer of cake on top of it. Optionally you can add raspberries in the middle.
Next, spread cool whip on top.
Garnish with the frozen chopped raspberries and remaining pistachios. Keep refrigerated for 1 to 2 hours before serving.