Put the mushrooms in a small bowl covered with 2 tablespoons of cold water.
Peel and finely chop the shallots. strip the tarragon leaves from the stems and chop.
Drain the mushroom liquid through a sieve lined with paper towel, retaining the liquid. Chop the mushrooms finely.
Melt 2 tablespoons of the butter and oil together over a medium to high heat in a heavy pan. When its foamy add the beef and let it brown for a minute to get a good colour.
Turn the meat in the oil mixture until all the sides are seared then transfer the meat to a roasting dish on top of a rack.
Put the meat in a preheated oven at 190C/375F/170FAN/Gas5. For medium rare roast it will need about 15 minutes a pound or 500g, internal temperature 55C/130F.
When the meat is cooked to your liking place it on a carving tray and cover it loosely with foil.
Over a medium heat add the chopped shallots to the pan used for searing the beef. Stir for a few minutes until the shallots are translucent.
Add the wine to the pan and bring to the boil. Stir thoroughly to loosen all the residue at the bottom of the pan.
Let the mixture reduce by half and add in the chopped porcini mushrooms.
Add the stock and mushroom juices to the pan and continue to simmer until the sauce is thick.
Add the remaining butter to the pan along with the chopped tarragon.
Check the seasoning and carve the meat into thick slices to serve.
Notes
Disclaimer:The nutritional information provided is approximate and is calculated using online tools. Information can vary depending on various factors, but we have endeavoured to be as accurate as possible.SUBSTITUTIONS
beef - if this cut isn't available then use any part of the fillet or tenderloin and use the same instructions.
wine - use twice the amount of stock instead if you prefer not to use wine.
porcini mushrooms - try other dried mushrooms or add some chopped fresh mushrooms with the shallots.
tarragon - use a teaspoon of dried tarragon in place of one tablespoon of fresh tarragon.
📖 VARIATIONS
sauce - try this sauce with any meat, such as duck, lamb or any steak to make it special.
tarragon - vary the herbs according to the meat. Try rosemary or mint with lamb, pork with sage or thyme with beef for a change.
🍽 EQUIPMENT
roasting pan with a rack
heavy based frying pan for the beef and sauce
meat thermometer
STORAGEIf you do have any meat left over it can be safely left covered in the fridge for three days or frozen for 3 months.I like to use the leftovers in stir fries.