Prep the vegetables: Wash the zucchinis, trim the ends, and slice into rounds or half-moons. Chop the onion, mince the garlic, and pick the basil leaves from their stems.

Sauté aromatics: Warm the olive oil in a large pot over medium heat. Add the chopped onion and a pinch of salt. Cook 4–5 minutes, stirring often, until soft, translucent, and lightly golden at the edges. Add the garlic and cook 30–60 seconds until fragrant.

Cook the zucchini: Add the sliced zucchini. Season with a small pinch of salt and pepper and toss to coat in the oil. Cook 5–7 minutes, stirring occasionally, until slightly translucent and releasing some juices.

Add broth and simmer: Pour in the vegetable broth and scrape up any browned bits from the bottom of the pot. Bring to a gentle boil, then reduce heat, cover, and simmer about 10 minutes, or until the zucchini is very tender and easily pierced with a fork.

Blend with basil and lemon: Remove the pot from the heat. Add the basil leaves and lemon juice. Use an immersion blender to blend directly in the pot until completely smooth and silky. (If using a countertop blender, work in batches, vent the lid, and cover with a towel to let steam escape.)

Add the creamy swirl: Taste and adjust salt and pepper. Swirl in the ricotta or cashew cream until the soup turns velvety and pale green. Keep the heat low or off so the cream stays smooth and doesn’t split.

Finish and serve: Ladle into warm bowls. Drizzle with extra virgin olive oil, top with a few basil leaves, and sprinkle with red pepper flakes if you like heat. Serve hot.