Fairly straightforward, and as it sounds. The sauce was sautéed red onion and coarsely diced Granny Smith apples, to which I added some whole grain and Dijon mustard. Deglazed with cider vinegar, and then added a stock cube along with some water. Reduced by about half, and stirred in some cold butter. Parsley added right before serving.
by Cipriano_Ingolf_Oha