1. Place potatoes into cold water and bring to the boil. Reduce heat and simmer gently. After 10-15 minutes, pierce with skewer to ensure potato is quite firm in centre. Remove from water and cool.
2. Peel skin off potato and grate. Season with salt and pepper. Add a tablespoon of melted butter and chopped chives.
3. Press potato mixture firmly into a round pastry cutter to form rosti.
4. Heat pan and add tablespoon of butter and splash of olive oil to prevent butter burning. Fry rosti on each side until golden.
5. Mix crème friache with chopped dill.
6. Assemble with a handful of roquette, smoked salmon, and finish with crème friache, salmon roe and a drizzle of lemon infused olive oil.