8 large (about 2kg) desiree potatoes, peeled
Sea-salt flakes and freshly ground black pepper, to season
2 Tbsp finely chopped chives
2 tsp finely chopped thyme leaves
50g butter, chopped, softened
2 Tbsp extra virgin olive oil
Put potatoes in a large saucepan. Cover with cold water and season with salt. Bring to the boil over a medium heat. Simmer for
10 minutes or until almost tender. Strain into a colander and set aside for 15 minutes to cool. Refrigerate uncovered for 1 hour or until cold.
Coarsely grate cold potatoes into a large bowl. Add chives and thyme then season. Shape into 12 discs, about 1cm thick, pressing firmly to hold their shape.
Melt 1⁄2 of the butter in 1 Tbsp of the oil in a large non-stick frying pan over a medium heat. Add 1⁄2 of the rosti and cook, turning occasionally, for 10 minutes or until golden and crisp. Repeat with remaining rosti, butter and oil.
Arrange on freezer-proof trays in a single layer and freeze for 6 hours or overnight until frozen solid. Remove from trays and transfer to a labelled zip-lock bag or air tight container. Keep in freezer for up to 1 month.
On the day:
Preheat oven to 180°C. Line 2 oven trays with baking paper. Arrange rosti on trays and roast for 30 minutes or until hot and crispy. Serve.