Time for a recipe. This recipe is one I learned at the Stone Table, the restaurant I am interning at. They put it on the spinach salad they serve, and it is amazing. Sweet and sour and it looks amazing!
They keep it simple, and don't have a set recipe, so I just guessed, and you will have to guess also. (Just use those cooking instincts!)
1 red onion
red wine vinegar
Cut the onion in half, the cut it so it will be in slices, not diced. Separate them and put them in a pot. Add red wine vinegar, for one onion I would guess between 1/4-1/2 c. though, I just guessed. Take a handful of brown sugar and put it on top of it all. Turn on the heat, around medium and let it cook down. I used a lid part of the time to keep it from boiling off too much moisture. The onions will be cooked when they are pink and translucent. Store in the fridge, use on salads and sandwiches.