Melt the butter in a pan on medium heat. Once melted and hot, add cinnamon stick and saute for 30 seconds.
The add chopped onion, garlic and celery. Sprinkle the salt and mix.
Cook till onions get translucent and light pink in color.
Then add all purpose flour. Mix and cook with stirring constantly for about 1-2 minutes or till the rawness of the flour goes away.
Now add chopped tomato and broccoli florets.
Add water or vegetable stock. Also add remaining salt.
Bring it to a simmer. Let it simmer for 15-20 minutes, or till the broccoli gets softened.
Turn off the stove.
Now using immersion hand blender, grind it into smooth puree.
If using grinder or blender, then let the mixture cool down slightly, drain the liquid and make smooth puree. Pour the puree and strained liquid back to the pan.
Now again turn on the stove on medium and bring it to a simmer.
Add black pepper powder and grated nutmeg. Stir well.