12 cups broccoli florets, stems, and stalks cut into 1-inch
pieces (about 1 large head)
3 ounces Parmigiano-Reggiano, grated
2 tablespoons lemon juice (from 1 lemon)
Kosher salt and freshly ground black pepper
4 slices hearty white sandwich bread, crusts removed and
cut into ½-inch dice
Melt 3 tablespoons of the butter in a large Dutch oven or
soup pot over medium-high heat. Add the onion, celery,
and garlic and cook, stirring, until the vegetables are
softened but not browned, about 5 minutes (reduce the
heat if the butter begins to brown). Stir in anchovies, if
using, and cook until fragrant, about 30 seconds.
- Add the flour and cook, stirring constantly, until all the
flour is absorbed, about 30 seconds. Stirring constantly,
slowly pour in the milk, followed by the stock. Stir in the
baking soda and broccoli florets and bring to a boil, then
reduce the heat to maintain a simmer, cover, and cook,
stirring occasionally, until the florets are completely
tender and olive green, about 20 minutes. - Working in batches, transfer the mixture to a blender,
add the Parmesan, and blend, starting on low speed and
gradually increasing to high, until completely smooth,
about 1 minute; add additional stock or water if necessary
to thin to the desired consistency (I like mine thick). Pass
through a fine-mesh strainer into a clean pot.
(Alternatively, use an immersion blender to puree the
soup directly in the original pot.) Whisk in the lemon
juice and season the soup to taste with salt and pepper.