Process biscuits in food processor until finely crushed - or smash them up in a sealed ziplock bag with a rolling pin!
Add melted butter to biscuit crumbs and mix thoroughly to combine.
Lightly grease the base of a 25cm or 9 1/2 inch loose-bottom tart tin, and line the base with baking paper (see notes).
Place biscuit mixture into tin and press the biscuits firmly and evenly into the base and up the sides of the tin (see notes).
Place biscuit base in freezer while you prepare the filling - uncovered is fine but place it on a large plate or you could end up pushing out the bottom insert by accident - done that!
Roughly chop the chocolate, and combine with cream in a medium saucepan (see notes).
Constantly stir over low heat until chocolate is melted and no lumps remain - set aside.
In a small microwave safe bowl heat raspberry jam, then strain to remove seeds (see notes).
Add Frangelico to jam, mixing to combine.
Remove biscuit base from freezer and using a pastry brush paint an even layer of jam onto the base of the tart.
Gently tear the raspberries into 3 to 5 pieces each and evenly distribute over the jam layer (see notes).
Pour chocolate and cream mixture over raspberries.
Place in fridge to set for 3.5 to 4 hrs or overnight (see notes) - remember to place the tart on a large plate again!
Decorate with reserved raspberries, and dust with icing sugar.