1. For the beetroot cure, blitz the beetroot to a smooth purée and put in bowl.
2. Combine the dill, sea salt, caster sugar, honey, black pepper and mustard.
3. Roll out a large piece of cling film and sprinkle the base with half of the beetroot mixture. Place the salmon skin side down on the beetroot mixture and top with the remaining mixture.
4. Wrap the salmon tightly with the cling film and give it an extra layer if you need to. Place the wrapped parcel in a high-sided dish and weight it down with a plate and some full cans or whatever heavy item you have to hand.
5. Leave the salmon to cure in the fridge for up to 5 days turning half way through. The dish will fill with juices but don’t be too concerned about draining them until you are ready to serve.
6. For the cucumber pickle, in a bowl mix together the sugar and vinegar until the sugar has dissolved. Mix in the salt and shallots and then add the cucumber slices. Cover with cling film and leave in the fridge for at least 2 hours or overnight.
7. For the dill crème fraîche, mix the dill, crème fraiche, lemon juice and black pepper in a bowl. Cover with cling film and leave in the fridge for at least 2 hours or overnight.
8. When you are ready to serve, unwrap the salmon and rinse off the cure under cold running water. Pat dry then slice thinly with a large knife. Arrange crisp breads on each serving plate and top with the slices of beetroot gravadlax and dollops of the dill crème fraîche and a small mound of cucumber pickle to each one. Garnish with the watercress and dill sprigs to serve.