Step 1

Place large pot over medium heat and melt butter. Add onion and sweat, about 5 minutes.

Step 2

Whisk in flour and cook for about 2 minutes.

Step 3

Stir in chicken stock and season generously with salt and pepper.

Step 4

Stir in celery and broccoli and bring to a boil, then reduce heat to medium-low. Let simmer until vegetables are tender, about 15 minutes.

Step 5

Stir in milk and continue to simmer until soup is thick enough to just coat the back of a wooden spoon, 2 to 3 minutes. (soup should still have a 'soupy' texture)

Step 6

Remove pot from heat and stir in cheddar in small handfuls, waiting until cheese melts to add more cheese.

Step 7

Season with salt and pepper and top with more cheddar. Serve.