For the stroganoff, place the oil in a hot frying pan, add the pork and cook on both sides until browned.
Add the spring onions, paprika and white wine, bring to a simmer and reduce for five minutes.
Place the cream into a jug, stir in the lemon juice and leave for 10 minutes. This then becomes soured cream.
Fold the cream into the stroganoff, just before you serve it.
For the rösti, combine the grated sweet potato, corn flour, parsley, apple and spring onion in a large bowl.
In a small frying pan heat the oil. Add the rösti mixture pressing down on it to make a large rösti. Cook for 5-7 minutes on a low heat and turn over. Continue to cook for four more minutes, or until browned.
Serve the rösti on a warm plate with the stroganoff.