Made a lovely meal last night (even if I say so myself!) adapted from the Fast 800 recipe book
Pork tenderloin/fillet - sliced into large chunks (1 fillet divided into enough pieces to share between three, so around 3-4 pieces, depending on the size of your fillet)
In a frying pan, melt a large knob of butter, and add a little oil (stops the butter burning) and sauté one small apple, sliced (skin on) and two sliced leeks. Cook for a few minutes until soft.
Add 200ml chicken stock (made with half a chicken stock cube), and a teaspoon of Dijon mustard, and 3 tablespoons of full fat creme fraiche. Cook until the apple is soft.
I then added about 12 cubes of frozen whole leaf spinach and continued to simmer until the spinach was cooked through.
Season with freshly ground pepper and sea salt flakes.
Put the sauce to one side while you cook the pork. Get a frying pan very hot and add some olive oil. When it's smoking hot add the pork, making sure it's all in one layer. Season with salt and pepper. Sear it for around a minute on either side - you're not aiming to cook it through, just to get some decent colouring on the pork.
When it's nicely browned on both sides, put the sauce back on to the heat and then stir the pork in to finish its cooking. This will only be a matter of a few seconds really. If you overcook the pork it will go very tough, very quickly.
Oh, and despite what a lot of people think, it's OK to eat pork fillet still slightly pink. You can double check by cutting one of the pieces to make sure it's not too pink, but a little pink means it will still be nice and tender.
I served this with asparagus spears that I'd sautéed in butter.