Well, it didn't turn out to be what I expected, since I didn't have exactly what I thought I had in the cupboards, but it's turned out really good.
I melted and slightly browned some butter, cut a couple of rashers of bacon into chunks and fried those lightly in the butter. In went enough flour to make a roux, stirry stirry stir; turned it into a sauce with half pork stock, half milk; cooky cooky cook; added a generous shake of powdered porcini mushrooms, adjusted seasoning, and finished off with a sploosh of one of my favourite sherries. That's going with fusili when he gets home.