Cut the rind off of the brie and discard. Cut the brie into small pieces. Set aside.

Carefully wash the leeks and pat dry. Clean the leeks thoroughly, Be aware that dirt accumulates in the stem. Cut the leeks into thin rings. Set a few aside for garnish, if desired.

Peel and dice the sweet onion.

Place the unsalted butter in a medium-sized saucepan over medium heat.

When the butter has melted, add the onions and the leeks and cook, stirring occasionally

until they are soft and transparent.

Season the leeks and onions with salt and freshly ground pepper to taste.

Sprinkle the flour over the leeks and onions and sauté until the flour is absorbed.

Add the vegetable broth and the milk to the pan. Stir to combine everything. Bring the mixture to a boil, then turn the heat down to low and add the cheese.

Simmer for about 5 minutes more over a low heat, stirring occasionally until the cheese has thoroughly melted into the soup.

Remove the soup from the heat. Transfer to a large soup terrine or divide the soup into 4 bowls.