Make vanilla ice cream according to the recipe but add only ONE
tablespoon of vodka instead of 1 ½ to make the ice cream a bit firmer.
My machine makes 1L at a time so I did mine in 2 batches. Alternatively you can whip the ice cream with a stick mixer or similar.
Spread and press ice cream into a loaf tin. Smooth the top of the ice cream. Cover
with cling wrap and place in the freezer between ice cream batches and
while you make the jelly.
Make jelly. Whisk jelly sachets into boiling water in a jug until
dissolved, add fridge cold water and whisk together. The mix should be
still just warm. Let it cool off until lukewarm if still too hot.
Remove loaf tin from freezer and pour lukewarm jelly over the top of the ice cream. Make sure to do it slowly and to move the jug around and over the ice cream. When the jelly hits the ice cream it will melt it very slightly so if you pour it all into one spot you could end up with a hole full of jelly in your cake! Cover with cling wrap and foil and freeze overnight.
To serve remove tin from freezer and let stand for 1-2 minutes. I ran a knife around the edge to separate the jelly layer from the sides and once I’d done that the whole thing popped out easily in one piece. Place a plate, platter or similar on top and turn the loaf tin upside down,
lift and remove the tin to turn out the cake.
Cut and serve immediately. Remaining cake can be stored back in the tin in the freezer in one piece, or cut into slices and stored in an airtight container in the freezer. Put baking paper between slices if stacking on top of each other so they don’t stick together.