Put the smoked salmon on a non-metallic baking tray or in a flat container, keeping the fish on its card from the packaging. Spread the beetroot over the top and around the edges of the fish and chill for 1 hour or more.
Remove the smoked salmon from the fridge and discard the beetroot. Wipe the fish with paper towels, then slice.
To make the cream, mix the crème fraîche, mustard, lemon juice and lemon zest. Season well and stir to combine.
To serve, arrange the fish on a few pieces of rye bread, scatter over a handful of pea- shoots, along with the radish and capers, and finish with a drizzle of the mustard cream.
Tip You can marinate the smoked salmon in the fridge for 2 days and make the cream 1 day before, then chill.
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