
Melt butter in a large pot over medium heat. Add thinly sliced onions and a pinch of salt.
Cook, stirring every few minutes, for 30 minutes until deep golden brown. Add a splash of water if they start to stick.
Stir in flour and thyme for 1 minute, then add the broth. Simmer 10 minutes.
Meanwhile, slice the baguette, top with Swiss cheese, and broil on a sheet pan 2-3 minutes until bubbly.
Ladle soup into bowls, float the cheesy toasts on top, and serve with salad.
Photo: DinnerDrop