Preheat oven to 400°F — cut ¼ inch off the top of the whole garlic bulb to expose tops of all cloves — place on aluminum foil drizzle with 2 teaspoons avocado oil and a pinch of kosher salt — wrap foil tightly into a sealed packet and roast for 40–45 minutes until cloves are completely soft golden and fragrant — allow to cool — this step can be done days in advance and stored in the refrigerator.
Place raw cashews in a heatproof bowl cover with boiling water and soak for 10 minutes — drain and set aside.
Bring a small pot of water to a boil — add fresh spinach and blanch for exactly 2 minutes — drain immediately and rinse under cold running water to stop cooking and preserve bright green color — squeeze out as much excess moisture as possible and set aside.
Heat a large Dutch oven over medium to medium-high heat and add a generous drizzle of avocado oil.
Drain marinated artichoke hearts thoroughly and add to hot pot in a single even layer — cook completely undisturbed for 5–6 minutes until cut sides develop a deep golden-brown crust — do not stir or move during this time as movement resets the browning process.
Transfer seared artichokes to a bowl and set aside — do not discard.
Reduce heat to medium-low and add another drizzle of avocado oil to the same pot.
Add thinly sliced leeks and a good pinch of kosher salt — cook for 10 minutes stirring occasionally until leeks are very soft slightly golden and fragrant.
Add diced yellow onion and cook for 5 minutes more until translucent and soft.
Stir nutritional yeast, ground coriander, and red pepper flakes into the softened leek and onion mixture — cook for 2–3 minutes stirring frequently until fully incorporated and the pot smells fragrant and slightly toasty.
Add drained rinsed cannellini beans to the pot and stir well to combine with the leek mixture.
Pour in vegetable broth and stir to incorporate everything — add bay leaves and thyme sprigs.
Bring to a boil over medium-high heat then reduce to a steady simmer — cover and cook for 20 minutes to allow beans to absorb broth flavors and soup to develop depth.
While soup simmers make the cashew spinach cream — combine drained soaked cashews in a high-powered blender.
Squeeze roasted garlic cloves directly from the cooled bulb into the blender — cloves should press out easily.
Add yellow miso paste and 1 cup cold water to the blender — blend on high speed until completely smooth with no remaining cashew pieces visible.
Add squeezed dry blanched spinach to the blender and blend again until spinach is mostly pureed and cream is uniformly green and smooth.
After 20-minute simmer remove and discard bay leaves and thyme sprigs from the soup.
Pour cashew spinach cream into the soup and stir to combine completely until cream is fully incorporated and soup has a consistent creamy texture.
Add reserved seared artichoke hearts back into the soup and stir gently to distribute.
Remove from heat — taste and adjust seasoning with kosher salt as needed.
Serve in bowls with toasted sourdough bread alongside and a drizzle of extra virgin olive oil over the top.