A while back there was a debate on whether slow cookers could do a credible rendition of caramelized onions. Well I promised my husband french onion soup today and then we were invited to an impromptu post New Years open house so I decided to try.
I started with approx 3.5 lbs onions that I thinly sliced. I added approx 3/4 stick of butter and a slosh of evoo to the slow cooker and let the butter melt on high. I then added the onions, some salt and sugar, gave it a good stir so the onions were well coated. I set the cooker on low at around noon, left for the party and got home around 4:00 to a heavenly smelling house. The onions were a dark tan but not quite "mahogany" so I stirred them and then set the cooker on high for another hour. At that point the onions were deep and rich in both color and flavor but still very liquid. If I was going to add them to pizza or use in a dip I would have transferred them to a skillet or shallow pan and let them cook down further. Since I was making the soup I just added a little flour, stirred and then added hot beef stock, cognac, dry vermouth and a pinch of thyme and let it cook on high for about another hour. It needed some salt and pepper so I added that and then turned on the broiler. I ladled the soups into bowls and topped with some bread I had made and frozen earlier that month and some grated Gruyere. I put the bowls under the broiler. I have to say it was as good as any other times I have made it but SO much easier since I got to leave the house in the middle! I was a sceptic but no more.
My next plan is to slice about 6-7 lbs next time and let them caramelize in the slow cooker all day while I am at work- at least 10-12 hours and then keep them in the fridge to add to other meals, as a topping for pizza or just as a guilty snack!