1. thinly slice all of the onions.
  2. heat a big pot. add 3 tbsp butter.
  3. add onions and cook for 10 minutes at medium high until softened. lower heat to medium low and cook for 1-2 hours, stirring frequently, until onions are golden-brown. deglaze with vermouth after an hour or so to prevent burning of the fond. add minced garlic and cook for another minute.
  4. add stock, herbs and brandy. simmer about 10 minutes.
  5. season with salt and pepper.
  6. thinly slice baguette. dip slices in olive oil to coat. arrange slices on a grate over a baking sheet. top with gruyere and parmesan. bake at 350 for 10 minutes.