Pretty much made this one up, but it is a common recipe and was always a favourite of mine whenever Mum cooked it.
I used a whole chicken and cut it up into pieces, it took ages but apparently it is cheaper than buying ready cut bits of meat - next time I might not bother going to all the trouble (actually since writing I have done it again, and again used a whole chicken - it was much quicker to cut up second time around).
Cut the chicken into bite-sized pieces, whatever size you like. Heat a knob of butter (approx 25g) in a large pan and thrown in the chicken along with a few sprigs of fresh tarragon and some seasoning. Cook until the chicken is slightly browned and remove from the pan, leaving the juices and any remaining butter in the pan.
Take a large white onion and finely chop. Chuck it into the pan and add 2 or so glasses of white wine. Cook this down for a while (10 minutes) on a medium heat until half the wine has reduced. Add 3 or 4 cloves of minced garlic and turn down the heat and let the garlic cook for a minute or two.
Now add half a pint of double cream, and into this crumble some nice cheese. I used some old dolcelatte I had hanging around in the fridge, and some grated cheddar (on second attempt I used Gruyère, both were equally as tasty). While that is all melting together nicely take a large bag of spinach and chop it up. Also chop up a few more sprigs of tarragon. Thrown all that into the cheese sauce, and the chicken, and stir well.
Now it is ready to go in the oven - I pour the whole mixture so far into a large terracotta dish and bung it in the oven at a medium to high temp for as long as it takes really - minimum of about half an hour to make sure the chicken is cooked through, but longer will make the sauce stickier and you might even get it to go a bit brown and crispy on the top.
Serve with pasta.