400 grams waxy or floury potatoes, scrubbed and grated
700 grams orange kumara, washed, peeled and grated
1 teaspoon sea salt
¾ cup sauerkraut
1 free-range size 7 egg
½ cup tapioca flour or spelt flour or regular wheat flour
cracked black pepper
100 grams crème fraîche
1 rounded teaspoon prepared horseradish
100 grams watercress leaves, woody stem removed
1 fennel bulb, sliced very thinly (retain fronds for garnishing)
300 grams smoked fish, remove any skin or bones
lemon wedges and olive oil, for drizzling (if desired)
Preheat oven to 180°C.
Rosti: Combine the potato, kumara and salt in a bowl. Stir well. Leave to sit for 15 minutes. Squeeze handfuls at a time to remove as much moisture as possible. Place into a new bowl. Add the sauerkraut, egg and flour. Mix well. Add a generous grind of cracked black pepper. Divide the mixture into 4 even portions.
Heat a generous glug of oil in a sauté pan over a medium / high heat. Cook one portion of the kumara / potato mixture at a time until golden brown on each side. The rosti can be delicate so take care when flipping. Repeat until all the mixture is used. Place the rosti on a tray lined with baking paper. Bake for 10-15 minutes until cooked through.
Horseradish cream: Mix together the crème fraîche and horseradish, season well.
To serve: Toss the watercress and fennel together. Break the smoked fish into chunks. Top each rosti with salad and a generous dollop of the horseradish sauce. Place chunks of fish on top and sprinkle with finely chopped fennel fronds. Serve with a lemon wedge and a drizzle of olive oil.