Saute the onion and garlic: Heat the olive oil and melt the unsalted butter in a large Dutch oven over medium heat. Then add the onion and cook for about 3 to 5 minutes until it’s soft and translucent. Now, add the garlic to the pot and cook for another 30 seconds until it’s aromatic.
Add the zucchini and cook: Season with salt and pepper. Then add the chopped zucchini, dried oregano, and dried thyme. Now, cook for another 5 minutes stirring occasionally.
Add the potatoes and broth: Stir in the potatoes, vegetable broth, and Worcestershire sauce. Now, bring to a boil, partially cover the pot, reduce the heat to a simmer, and cook for about 20 minutes or until the potatoes are fork tender.
Puree the soup: Once the potatoes are cooked, remove the Dutch oven from the heat. Then use an immersion blender, or carefully transfer the hot soup to a blender and puree/blend until smooth.
Add the cream and serve: Place the blended soup back over low heat and then whisk in the heavy cream until smooth. Now, serve the zucchini soup hot to enjoy.