• 3 large whole desiree potatoes, peeled
• 5 Tbsp sour cream
• 3 Tbsp horseradish cream
• 3–4 baby beetroots, washed, trimmed, leaving 1cm stem intact
• 1 tsp caster sugar
• 1 tsp sea-salt flakes, plus extra, to season
• 21⁄2 Tbsp extra virgin olive oil, plus extra 120ml, for frying
• 1 large beetroot, coarsely grated, excess juice squeezed out
• 21⁄2 Tbsp flour plain
• Freshly ground black pepper, to season
• 500g piece boneless, skinless salmon
• 1⁄2 bunch chives, finely chopped
• 2 Tbsp caviar
• Lemon cheeks, to serve
Put potatoes in a large saucepan of cold, salted water. Bring to the boil over a medium-high heat, cooking for 15 minutes or until cooked, yet still very firm. Drain and set aside to cool to room temperature.
Combine sour cream and horseradish in a small bowl. Cover and set aside in fridge.
Slice baby beetroot finely using a knife or mandolin. Transfer to a large bowl. Add sugar and salt, and toss well. Drizzle with 2 Tbsp of the oil, toss again and set aside at room temperature to soften slightly.
Meanwhile, use coarse side of a box grater to grate cooled potatoes onto a tray, making sure not to crush potato pieces too much. Scatter over large beetroot and flour, then season. Gently toss together to combine. Shape mixture into patties the size of a tennis ball without crushing the grated pieces.
Heat the extra 120ml oil in a large frying pan over a medium heat. Fry rosti patties, in batches to avoid overcrowding pan, for 3 minutes each side or until cooked through and crispy on the outside.
Slice salmon into 1–1.5cm slices. In another frying pan, heat the remaining oil over a high heat. Season salmon, then sear for 45 seconds on each side.
Put 2 rosti on each plate with a dollop of horseradish mixture, 2–3 salmon slices and a few slices of baby beetroot. Scatter over chives and crown with a spoonful of caviar. Serve with lemon on the side.