1. In a large bowl, place the cream, milk icing sugar and vanilla and whisk to dissolve the icing sugar. Pour into a large 20 x 30cm metal slice tin and freeze for 2-3 hours or until just frozen.
2. Meanwhile thin the raspberry jam down with the water in a small bowl and set aside. Roughly chop the shortbread fingers into small chunks and place into a bowl and set aside.
3. Remove from the freezer and break apart into small pieces using a butter knife. Place the pieces into a food processor and blitz until just smooth and creamy.
4. In a large loaf tin spoon 1/3 of the ice-cream into the base of the tin and add 2 – 3 tbsp of the thinned raspberry jam and dollop over the top of the ice-cream. Add 1/3 of the chopped shortbread pieces and sprinkle over the top. Repeat with the next layer of ice-cream, raspberry jam and shortbread pieces and repeat until all the mixture has been used and you have finished with a layer of jam and shortbread on top.
5. Place back into the freezer and freezer for 3-4 hours or until firm and frozen through.
6. Remove and scoop with a warm ice-cream scoop into a waffle cone or bowl.