Mussels in WIne

What can you make with a bag of frozen mussels, a bottle of open rose wine, and half an onion?
Mussels in wine sauce of course!

From the freezer: mussels
From the fridge: butter, bottle of rose already open from yesterday, half an onion (from this morning's omelette)
From the pantry: spaghetti

I made a steaming liquid with wine, some mushroom broth from Friday, and some browned onions
I steamed the mussels in it.

I made a roux with butter and flour.