Pour powdered gelatin into a small bowl and cover with hot water. Stir thoroughly until gelatin is dissolved and there are no lumps.
In a double boiler or microwave, melt the chocolate. Set aside to cool, stirring occasionally.
Pour the milk and cream into a saucepan with the vanilla extract and sugar. Stir to combine and bring to a boil, then remove from the heat. Add the dissolved gelatin and stir until completely blended. Divide the cream mixture into 2 equal parts. Add the melted chocolate to one of them and mix thoroughly. Set aside to cool for 10 minutes.
Prepare 2 glasses. Into each of them, put a cream layer, alternating with a chocolate layer and a layer of raspberries. Continue until all the ingredients are used up. Cover and refrigerate for at least 3 hours or overnight. Just before serving, sprinkle with slivered almonds.