Start by gathering your equipment: a large stockpot, a sharp knife, a wooden spoon, and a measuring jug.
Heat the stockpot over medium heat and add a splash of oil until it shimmers and starts to gently ripple.
Sauté the diced onion and minced garlic in the hot oil until fragrant and translucent, about 3-4 minutes, stirring occasionally. The onions should turn soft and slightly golden.
Add the chopped chicken to the pot, stirring occasionally, until it’s lightly browned and cooked through, about 6-8 minutes. You should see the chicken turn white and slightly crispy edges form.
Pour in the chicken broth and bring it to a gentle simmer. As it warms, add sliced zucchini and chopped spinach directly into the broth, allowing the vegetables to start softening.
Let the soup simmer gently for 10-15 minutes, until the zucchini is tender and the flavors meld together. The broth will turn a vibrant green with tender vegetables floating in it.
Taste the broth and season with salt, pepper, and chopped thyme as desired. For a richer, velvety texture, stir in the heavy cream and cook for another 2 minutes.
Turn off the heat and let the soup rest for 5 minutes to allow the flavors to settle and intensify.
Spoon the hot, steaming soup into bowls, garnishing with fresh herbs or a squeeze of lemon if desired. Serve immediately for the best flavor and texture.
