Mushroom and Mascarpone Sauce for Pasta

This isn't low fat, for sure, but it got supper on the table in 15 minutes and was warming and filling on a freezing foggy Autumn night.  Whilst your pasta is cooking, what ever shape you fancy, saute a finely chopped onion in a tablespoon of olive oil until starting to soften, then add a clove of crushed garlic and stir for a minute or two.  Then add a punnet of chopped mushrooms, whatever you have to hand - I used two wonderful big Portobello mushrooms from the Riverford veg box - and saute for a minute or two over a brisk heat until lovely and juicy.  Strip three or four small sprigs of fresh thyme and stir into the pot.  Now, stir in around half a tub of mascarpone, about 125g.  I know, I know, stop whingeing, it is for 2 people!  Allow it to melt and bubble into the mushrooms.  Taste and adjust the seasoning, stirring in a couple of tablespoons of grated parmesan.  Drain the pasta, reserving a little of the cooking water.  Add drained pasta to the pan and stir well with the sauce, adding a little of the reserved cooking water if needed.  Add some chopped parsley if you have it. Spoon into hot bowls, sprinkle a little more parmesan over, and tuck in!  Now what to make with the remaining mascarpone?  Same again?  Or spoon it through a hot tomato sauce for another creamy pasta option!