Heat the heavy-bottomed pot over medium heat and add a tablespoon of olive oil. Once shimmering, add the chopped onion and sauté until translucent and fragrant, about 5 minutes, listening for a gentle sizzle and watching for the onion to turn clear.
Add the minced garlic to the pot and cook for another minute, until you smell a warm, fragrant aroma. Stir frequently to prevent burning, and watch for the garlic to become golden and fragrant.
Introduce the broccoli florets and diced potato (if using), stirring to coat them with the aromatics. Cook for 2-3 minutes, watching the broccoli turn a vibrant green and the potato start to soften slightly.
Pour in the vegetable broth, bringing the mixture to a gentle simmer. Cover the pot and cook until the broccoli and potatoes are tender, about 7 minutes. You’ll notice the broth bubbling softly and the vegetables becoming soft when pierced with a fork.
Remove the pot from heat and carefully use an immersion blender to blend the soup directly in the pot until smooth and velvety. If you prefer a chunkier texture, blend only part of the soup or pulse briefly.
Stir in the nutritional yeast, salt, and pepper, then return the pot to low heat. Let the soup simmer gently for 10 minutes, allowing the flavors to meld and the cheese-like richness to develop. You’ll notice the soup slightly thickening and becoming more fragrant.
Taste the soup and adjust seasoning with more salt or pepper as needed. If it’s too thick, add a splash of broth or plant-based milk to reach your desired consistency.
Once seasoned perfectly, turn off the heat and let the soup sit for a minute or two. Serve hot, garnished with fresh herbs or a drizzle of olive oil if desired, for an inviting, velvety bowl of bright green goodness.