Goldrush Girl's Carmelised Onion & Sausages

I begged for this recipe and Goldrush Girl kindly (& wisely) obliged. She also began it with a confession that proves she's one of us (one of us, one of us): I should confess, my dear Britomart, that there is not an actual recipe as such. I don't hold with following recipes because I don't like being MADE TO OBEY INSTRUCTIONS. But this is what I cobbled together, and it goes really well with very good quality butcher-made English sausages, which should be browned in a frying pan then oven-cooked till nice and crispy. All amounts are entirely up to you.

Chop an onion or two into chunks (rather than slices). Melt a bit of butter in a lidded saucepan and throw the onion in. Put the lid on and turn the heat down very low. Leave for 20 or 30 minutes. You can sprinkle a little soft brown sugar on it if desired. Occasionally you can shake the pan around a bit, or give it a little a scrape if it starts to burn, but it's best if the onion sort of sticks to the bottom of the pan a little bit.

When the onion's deliciously soft and brown and sweet-smelling (with luck, this will be the same time as the sausages are ready), scoop some lovely thick creme fraiche into the saucepan along with as much wholegrain mustard as you desire, and a bit of freshly-ground black pepper. Stir together... the onion juices are divine with the creme fraiche.

Plop some of the sauce on your plate with the sausages. A vegetable or two would be good (braised fennel works well) and maybe a starch (mash, or mashed sweet potatoes, even better). The other day I had it with a beetroot salad on the side, and that was lovely.