INSTRUCTIONS
1. Heat the butter in a large saucepan over medium heat. Add the onions with a pinch of salt and patiently cook, stirring often, until caramelized, 15-20 minutes. If the pan becomes too dry during cooking, add a splash of water (1-2 tablespoons).
2. Add the flour and mix with a wooden spoon for about 1 minute until it starts to brown.
3. Add the wine. Mix well. Cook for about 2 minutes until most of the wine evaporates.
4. Add the beef broth, black pepper, and dried thyme. Bring to a boil over high heat.
5. Reduce the heat to medium-low and simmer, uncovered, stirring often, until the soup is noticeably thicker, about 20 minutes. Serve immediately.