Heat olive oil in a large pot over medium heat until it shimmers and begins to smell fragrant.
Add diced onion to the pot and cook, stirring occasionally, until translucent and soft, about 5 minutes. The onions should be fragrant and slightly golden.
Stir in the minced garlic and cook for another minute until it becomes fragrant and slightly golden, filling the kitchen with a warm aroma.
Add the chopped broccoli florets to the pot, stirring for 2–3 minutes until they start to soften and turn bright green.
Pour in the vegetable broth, bringing the mixture to a gentle simmer, then cover and cook for 10–12 minutes until the broccoli is tender and easily pierced with a fork.
While the soup simmers, drain and blend the soaked cashews with 1 cup of water until completely smooth and creamy, which will add richness later.
Use an immersion blender directly in the pot or carefully transfer the soup to a blender, then blend until you reach your desired smoothness, leaving some texture if preferred.
Stir in the cashew cream, nutritional yeast, Dijon mustard, and ground nutmeg, whisking until well combined and heated through, about 2 minutes.
Taste the soup and adjust seasoning with salt and pepper, adding more nutritional yeast if you want a cheesier flavor.
Remove the soup from heat and let it sit for a couple of minutes to settle and deepen the flavors.
Ladle the hot soup into bowls, garnish with fresh herbs if desired, and serve immediately for a velvety, comforting meal.
