Nothing could be easier to prepare for the big day. We started the birthday gravlax on the Tuesday night prior to the Sunday, and we thought it was perfect, but three days is fine.
Purchase a piece of fish (about 1kg of salmon or ocean trout), then mix equal amounts of sugar and rock salt (about 500g each), with some crushed garlic cloves some fresh dill and lemon (or lime) juice. Place half of the mix underneath the fish in a big glass Pyrex baking dish, cover the fish with the rest and pour over about 75ml of vodka (or gin or vermouth). Cover with cling wrap and place in the fridge with something heavy on top (cans or full bottles of tonic water). Half way through your curing turn the fish over and return to the fridge. We serve it with fresh rye bread and yoghurt cheese. If you would like to try the yoghurt cheese place 1kg of Greek yoghurt in a colander lined with muslin. Mix in a teaspoon of salt and leave to drain overnight in the fridge.
On the day, wash off the curing mix from the fish under the tap. Pat dry with paper towel. Check for any bones (they are easier to remove once the fish is firm and cured) and slice as thinly as you can. We serve it on a bed of dill (or fennel). Mix some horseradish (fresh or from a jar) into the yoghurt, slice your bread and enjoy.