Pre-heat the oven to 180C/350F/Gas 4. Coarsely grate the potatoes, place in a clean tea towel and wring out as much moisture as possible before placing them in a bowl. Add half the butter, season and mix well. Heat a 20 cm (8 inch) non-stick frying pan, add the oil and the remainder of the melted butter. Put the grated potatoes into the frying pan and cook on a fairly high heat until the underside is browned. Remember to shake the pan so the potatoes do not stick. Next, turn the rosti over and continue to cook, shaking the pan occasionally until the other side is browned. Place the rosti in a preheated oven for 15-20 minutes or until the potato is cooked through. Remove from the oven and keep warm.
To make the Hollandaise Sauce place the egg yolks, salt and sugar in a food processor. Heat the wine vinegar, lemon juice and white wine in a small saucepan and reduce by half. In another small saucepan melt the butter and allow to bubble, taking care not to burn it. Set the food processor to high speed and pour in the warm, reduced wine vinegar liquid, followed by the hot melted butter, which should be added very slowly.
For the streaky bacon pre-heat the oven to 180C/350F/Gas 4. Lay the rashers of bacon on a baking tray and cook in the oven at the same time as the rosti until crisp. Remove from the oven, set aside and keep warm. Cut the asparagus to about the length of your middle finger. Using a potato peeler lightly peel the bottom inch towards the cut end so you produce a white stalk and a plump green top. This all sounds a bit cheffy, I know, but think presentation, presentation. Reserve the trimmings to make asparagus soup. Blanch the asparagus in a saucepan of boiling salted water for 2 minutes. Drain immediately, and return to the same pan adding a generous knob of butter and seasoning to taste.
To serve, with a sharp knife, cut the warm rosti on a chopping board into 6 equal sized wedges, and place 1 in the centre of each serving plate. Lay a mound of asparagus on top of the rosti, spoon over the hollandaise and finally top with a strip of crisp, streaky bacon. Serve immediately.
Recipe taken from Cooking at Morston Hall, available to buy from www.galtonblackiston.co.uk for £12.95
3 bunches Norfolk asparagus
Salt and pepper
6 rashers smoked streaky bacon, thinly sliced
For the Rosti Potatoes:
450g (1lb) King Edward potatoes
55ml (2 fl oz) melted butter
55ml (2 fl oz) rapeseed oil
For the Hollandaise Sauce:
3 egg yolks
Pinch of salt
½ tsp caster sugar
1 tbsp white wine vinegar
1 tbsp lemon juice
1 tbsp white wine
175g (6 oz) butter