Heat the butter and oil in a frying pan, add the onion and fry for 5 minutes until lightly browned. Stir in the cup mushrooms and garlic and cook for 4 minutes. Stir in the paprika and cook for 1 minute.
Pour in the vodka. When it is bubbling, flame with a match and stand well back. Once the flames have subsided, stir in the stock, cinnamon and mace and season with salt and pepper. Simmer for 3–4 minutes.
Add the wild mushrooms and cook for 2 minutes. Stir in 2 tablespoons of the crème fraîche.
Spoon the stroganoff on to serving plates and top with spoonfuls of the remaining crème fraîche, a sprinkling of paprika and a little parsley. Serve with sweet potato mash.