Slice zucchini lengthwise, and scoop out most of the seeds. Cut zucchini into chunks.
Heat olive oil or butter in a large sauce pan over medium-low heat. Cook onion and garlic until it softens and becomes translucent, 7-8 minutes.
Add zucchini, and bring heat to medium-high, salt and pepper to taste, and cook until slightly softened.
Add vegetable stock and peppercorns and bring to a simmer over medium-low heat. Cover with a lid and simmer 12-15 minutes or until zucchini is tender (but not mushy).
OPTIONAL: Blanch for herbs to preserve their bright green color. Bring a small pot of water to a boil. When water is bubbling, add in your basil and parsley and blanch for about 30 seconds, then remove from heat, strain, and immediately move to a bath of ice water. When herbs have stopped cooking, strain and move to a paper towel to remove excess water. You’ll notice the greens are very bright and vibrant, and this helps to keep the soup green, but it is not required.
Add in the blanched OR raw herbs to the stock, then transfer to a blender and puree with lime juice and zest—salt and pepper to taste.
Chill in the refrigerator overnight (the flavor will be more developeand serve with a dollop of yogurt or creme fraiche. Garnish with feta and fresh herbs and enjoy!