In a Dutch oven, heat a tablespoon of olive oil over medium heat. Add the chopped large yellow onion and cook for 5-7 minutes, stirring occasionally, until translucent and softened. Then, add three minced garlic cloves and sauté for an additional minute.

Pour in four cups of chopped zucchini, four cups of vegetable broth, one teaspoon of kosher salt, half a teaspoon of black pepper, and half a teaspoon of dried thyme into the pot. Bring the mixture to a boil, then reduce the heat and let it simmer uncovered for 15-20 minutes, or until the zucchini is tender and bright green.

Once the zucchini is cooked through, add one can of rinsed cannellini beans to the pot. Using an immersion blender, blend the soup until completely smooth and creamy.

Stir in one tablespoon of fresh lemon juice for a burst of brightness, along with a quarter cup of optional heavy cream for added richness. Taste and adjust the seasoning if necessary, then ladle your warm soup into bowls. Serve hot, garnished with croutons or fresh herbs for an extra touch.