The key to a good onion soup is caramelization. It takes time, but the results are worth it. I add extra nutrition to onion soup by adding spinach and beans, producing a heartier consistency. Hard to believe that this soup was mere peasant food and now costs a small fortune in restaurants! Make your own and you'll be swooning with love.
Ingredients
4 lbs onions, sliced in thin 3-4" pieces (white or yellow)
2 tbsp butter or oil
1 tbsp thyme, dried, or sprig of thyme
bay leaf
tt salt and pepper
3 tbsp tomato paste, or one Roma tomato, seeded and chopped very finely
2-3 oz red wine or brandy
2 cups chicken stock
2 cups beef stock
6 oz baby spinach, roughly chopped
1- 15 oz can of cannellini beans (white kidney beans) or navy, drained
Swiss or Gruyere cheese, grated
French bread
Instructions
Read Susie's Tips and Tricks below
1. In a large wide skillet turn heat to medium and add oil or butter, then add onions. (It appears to be a large quantity but then shrinks.) Do not rush and raise the temperature. Be sure to turn the onions every 4 to 5 minutes for good colour.
It takes approximately 40-50 minutes for a richly flavoured onion to be caramelized well. If they appear very dry and seem to be burning, lower your heat. As the sugars come out, you will want to ever so slightly lower the temperature.
2. Once the onions are well-caramelized, add a sprig of thyme (or dried thyme), tomato paste, and bay leaf. Let cook a few minutes, then add red wine. Remove sprig of thyme. Let cook off, then add chicken and beef stock.
3. Taste to determine if more salt and pepper is desired (some stock is saltier than others). Simmer and prepare bread. If desired you may add spinach and beans for extra nutrition.
Toast your bread and shredded cheese with soup in oven-proof bowls and melt in.
Susie's Tips and Tricks
Salt after caramelizing. Salt draws out moisture and thus it takes longer to get browned onions.
I skip flour for thickening this soup. Some recipes included it but why use it, its a stock-based soup.
Use 100% chicken stock if desired.
Don't bother using more expensive varieties of onions, once they are caramelized I couldn't tell the difference. Cut them up in spoon-size pieces (no one wants to slurp up a 6" onion string).
It takes time to caramelize onions. You will get best results keeping the temperature on the low end of medium. Then lower further as sugars come out. Look under strong light to see if they are truly well-browned. Rushing will cause the onions to burn.
It was believed that butter and oil together raises the temperature of the butter to prevent burning. Science says otherwise, use your preferred oil.
Cook's Illustrated has suggested to add a tsp of baking soda to usher along the caramelizing, I didn't like the results though. The colour of the onion turned a dreadful yellow.
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