Heat the vegetable oil in a large, heavy-bottomed frying pan. Finely chop the fresh tarragon.
Tarragon has a very distinctive, aniseed taste. It's quite strong by itself, but is lovely when it's used to flavour meats or sauces
Season the pork steaks on both sides with salt and pepper and then rub in the tarragon. Pop the pork steaks in the frying pan and cook for 4 minutes on the first side.
I use the packet to rub in the tarragon. It's a useful container
While the pork is cooking, start to prepare the sauce. If you used your hands to rub in the tarragon, make sure you wash them and any other cooking utensils or chopping board you used for the raw pork. Firstly, peel and chop the shallots very finely.
The shallots are tricky to slice finely, so make sure you have sharpened your knife.
Once the pork has been cooking for 4 minutes, turn them over and cook the other side for 4 minutes.
Slice the mushrooms finely and mince the garlic in a garlic crusher, or crush it under the flat of a knife and then chop it very finely.
The mushrooms just need to be wiped rather than washed.
If you have thin pork steaks, they should now be cooked. If they are thicker they will need a little longer. When they are golden on the outside, and no pinkness remains in the centre, remove them and set them aside. Cover the plate with tin foil.
The pork will release delicious juices that you will use later in the recipe.
Now melt the butter in the pan you were frying the pork in and add the mushrooms, shallots and garlic. It will take about 5 minutes for everything to soften.
The mushrooms, garlics, and shallots all cooking away in the pan.
Add the white wine to the pan with the mushrooms, and turn up the heat, using the wine to deglaze the pan of any crispy bits left over from the pork. Once it has cooked for about 2 minutes, and started to thicken, stir in the cream, mustard, and juices from the resting pork. Cook for another 2 minutes.
The sauce is starting to thicken and is now almost ready.
Transfer everything to a plate with the potatoes and peas, and enjoy!