Begin with the bread, cut the crust off. Slice the bread, lengthways, approximately 1cm thick. I ended up with slices measuring 19 x 9cm. You will need 4 slices. Blitz the crust and remaining bread to make breadcrumbs (stores well in the freezer). Spread both sides of the bread with a thin layer of butter.
Have a platter ready to assemble the cake on. Place the first buttered slice on the plate. Combine the salmon, cream cheese, creme fraiche, lemon juice, zest and horseradish. Stir well and add half of the dill. Place the salmon mixture on the first slice and follow with the second buttered slice.
Cut the avocado in half and peel, mash roughly with a fork. Add the lemon juice, chives and cucumber, season to taste with salt and pepper. Spread on the second layer of bread. Top with the third layer of bread.
Peel the prawns. Keep a few to decorate the cake, roughly chop the remaining. Place in a bowl and add the mayonnaise, creme fraiche, chopped red onion and dill. Add the zest and juice of the lemon and season with pepper and salt if it needs it. Spread the prawn mixture on the third layer of bread and top with the final slice.
Now place the cream cheese in a bowl and give it a good stir to loosen it. With a palette knife mask the cake with the cheese. The sides don’t have to be too neat as they will be covered with cucumber slices. Cut the cucumber so they’re a little taller than the cake. Arrange the slices all the way round. Top with a few prawns, petals, flowers and pea shoots.