Heat a knob of butter and a glug of olive oil in a frying pan until very hot. Add the steaks and cook for 1.5 minutes each side, then turn the heat down and cook for 4 minutes each side or until cooked to your liking.
Remove the meat and set aside in a warm place.
Add a bit more oil and fry the shallot until soft.
Add the mushrooms, put the lid on and cook until soft, stirring occasionally.
Add the garlic and thyme and cook for another minute with the lid off.
Add the brandy and cook with the lid off for another minute or two.
Add the honey, mustard, stock, and mushroom ketchup, and bubble for a minute.
Turn the heat off and stir in the crème fraiche. Turn the heat back on low and heat gently for a minute.
Serve the sauce with the venison and vegetables of your choice. If the venison has cooled down too much, heat it through in the sauce.