This is not your average broccoli cheese soup. It's smooth and creamy with layers of flavor you wouldn't expect. A decadent option uses truffle oil to finish the soup and flavor the crunchy croutons.
Trim the crust from the bread and transfer it to a mini food processor. Pulse several times until the bread is broken down into bite-sized, shaggy bits.
Transfer to a baking sheet and drizzle with truffle oil (if using) or olive oil. Toss well to coat and arrange croutons in a single layer on the baking sheet.
Bake for 8 minutes and stir the croutons. Return the bread to the oven and cook for another 8 minutes or until golden and crispy. Remove from the oven and set aside to cool.
FOR THE BROCCOLI POTATO CHEESE SOUP
Prep the broccoli by removing the florets and setting aside. Trim the tough end of the broccoli stems. Use a vegetable peeler to peel away the tough outer skin. Discard the peelings. Chop the stems into ½" pieces
Heat the olive oil and butter over medium-high heat in a large pot or Dutch oven. Stir in the onion and carrot and cook for 3-5 minutes until the onion is softened and slightly translucent, stirring occasionally. Adjust the heat down if the vegetables start to brown.
Add the chopped garlic and red pepper flakes and sauté for one minute. Sprinkle on the flour and stir into the vegetables until all the flour is absorbed by the oil and butter. Cook for one minute, stirring constantly.
Stir in the wine a little at a time, scraping the bottom of the pot to release any fond. Bring to a low bubble and cook for 2 minutes, then stir in the broth a little at a time until the soup stock is well blended.
Add the broccoli florets, stems and potatoes, thyme bundle and parmesan rind (if using) to the soup stock and bring to a boil stirring occasionally. When it just reaches the boiling point, reduce the heat to a simmer and cover with the lid slightly askew so the steam can escape. Cook for about 15 minutes or until the potatoes and broccoli are tender, stirring occasionally.
Stir in the cream and simmer for an additional 5 minutes. Remove the soup from the heat and use a pair of tongs to remove the parmesan rind and thyme bundle. Discard.
Add the grated gruyere cheese, about half a cup at a time, stirring after each addition until the cheese is melted before adding the next handful.
Blend the soup until smooth. You can use an immersion blender for this or a regular blender. For a regular blender, fill the container no more than halfway, secure the lid tightly and cover the top with a dish towel to avoid any splatters—Pureé in batches.
Process the soup until smooth. Taste for seasonings and adjust as necessary.
TO SERVE:
Ladle the soup into bowls and garnish with truffle oil and crispy croutons over each bowl. Sprinkle on additional gruyere cheese and mini-blanched broccoli florets, if desired.