1.2 kgmashing potatoes, such as Desiree, cut into 2cm dice150 mlpouring cream100 ml milk60 gmbutter, coarsely chopped, plus extra, melted, for drizzling2 garlic cloves, crushed8 thyme sprigs60 ml(¼ cup) olive oil2 small onions, thinly sliced on a mandolin, rings separated8 thick beef or lamb sausages (about 80gm each)To serve: hot English mustard
Cook potato in boiling salted water until tender (12-15 minutes). Meanwhile, heat cream, milk, butter, garlic and half the thyme in a small saucepan over medium heat until hot. Drain potato, return to pan, mash until fluffy, strain cream mixture over (discard solids), stir until smooth, drizzle with melted butter, season to taste and keep warm.
Heat oil in a large frying pan over medium-high heat until very hot. Add half the onion, stir occasionally until golden and crisp (1-2 minutes), remove with a slotted spoon, drain on absorbent paper and repeat with remaining onion. Add remaining thyme, fry until crisp (30 seconds), then drain on absorbent paper. Drain oil, leaving 20ml in pan, then add sausages and turn occasionally until golden and cooked through (6-7 minutes). Scatter sausages with onion and thyme and serve hot with mash and hot English mustard.