Soak the gelatine leaves in cold water until they are soft.
Split the vanilla pods in half and scrape out the seeds.
Place the milk, cream, sugar, vanilla and limoncello in a saucepan. Bring to a gentle simmer and then add the softened gelatine leaves. Stir to dissolve the gelatine.
Pour the liquid through a fine sieve into a jug and then into moulds.
Chill in the fridge until set (at least 2 hours).
Increase the oven temperature to 180'C.
Dice the butter. Split the vanilla pod and scrape out the seeds with the point of a knife.
Rub the butter, vanilla, flour, salt together and then knead until you have a firm ball of dough. Roll into a sausage in cling film and set in the freezer or fridge until hard.
cut into 1cm thick rounds and place on a lined tray with space between each one.
Bake in the oven for 10-12 minutes.
Return to the oven and bake for a further 3 minutes. When golden brown on the edges and firm in the middle, sprinkle with the caster sugar whilst still hot and then allow to cool.
Drizzle the spare limonello on each panna cotta, and serve with the short bread. Any spare biscuits can be crumbled on top of the panna cotta.
«For a vegetarian alternative, the gelatine can be replaced by agar agar. Use the powdered type, as it is easier to use. Use half the amount of agar for gelatine (4g agar agar instead of 8g of gelatine). »