Preheat overn to 400 degrees F.

Peel the onions, remove the roots, and slice thinly.

Melt the butter in a large saucepan over medium heat and cook the onions until soft and lightly colored.

Add the flour and cook until it starts to take on some color (1 to 2 minutes).

Deglaze with white wine and allow the liquid to reduce by half before adding the water.

Add the bouquet garni, season to taste, then reduce the heat to a gentle simmer and leave to cook for 45 minutes.

Optional: Add some glace de viande for more color.

Slice the baguette and lightly toast it in the overn, then lightly butter the top side of each slice and sprinkle with cheese.

Place the bread back in the oven until the cheese is just melted but not colored.Set aside.

Remove the bouquet garni from the soup and discard.

Optional: Whisk the port wine into the cream and ladle some hot soup into the cream to temper.

Off the heat, stir the cream back into the hot soup.