Make the chocolate pudding by following the package instructions, substituting heavy cream for milk and adding 1 tablespoon of vanilla extract. Chill in the fridge.
Cut the chocolate pound cake into small cubes and set aside.
In a large bowl, whip 3 cups of heavy cream and 3 tablespoons of sugar at high speed until stiff peaks form. Set aside.
Begin layering in a trifle dish: start with a layer of cake cubes.
Add a layer of chocolate pudding, followed by fresh raspberries, then whipped cream.
Repeat layers (cake, pudding, raspberries, whipped cream) until you have two layers of each.
Top the trifle with chocolate shavings and a few extra raspberries.
Chill before serving for the best flavor and texture.