1Dice up your onions, carrots and celery and sautee together in oil until soft.
2In the mean time, cut the head of broccoli into small florets. Toss in all of your cut broccoli and cover with 3 or 4 cups of broth. Cover and simmer for about 7 minutes or until broccoli stalks are fork tender.
3Remove from heat, stir in the 1/2 cup nutritional yeast and let cool.
4Use an immersion blender or transfer soup to blender in batches - puree until very smooth. You may need to add a bit of broth if it looks too think. Add salt and pepper to taste, or even some red chili flakes.