In a non stick pan on high heat saute the mushrooms in 2 batches in 45grams (1.5 oz) of butter until brown and remove to a large bowl.
Meanwhile flour the beef in batches and shake off the excess flour.
In the same non stick pan on high heat sear the beef in 3-4 batches in 20g (0.7 oz) of butter and a good splash of extra virgin olive oil and remove to the same bowl as the mushrooms.
In a large heavy based pot over low heat melt 30g (1oz) of butter and a good splash of olive oil.
Add the shallots and cook for about 5 minutes.
Add the garlic and cook for a further 3 minutes.
Turn the heat up to high and add the brandy.
Cook for a minute or 2 until almost all the brandy has been cooked off.
Turn off the heat and add the paprika and tomato paste and stir well.
Add the beef stock, meat and mushrooms and return to the heat.
Bring to the boil and reduce to a very low simmer and cook for about 2 hours, or until the meat is very tender. Stir regularly as the sauce will be quite thick and may stick easily. If too thick, a little water can be added.
Fold through sour cream.
Taste and adjust seasoning.
Transfer to serving dish and garnish with freshly chopped parsley.