In a large saucepan, melt butter over medium heat. Add all zucchini minus ¼ cup (you’ll use this as garnish) to pan. Cook until zucchini is soft and tender, about 15 minutes. Let cool completely.
In a small saucepan, toast pine nuts for about 5 minutes, until lightly browned. Remove from heat.
Once zucchinis have cooled, add cilantro, parsley, mint, olive oil, lemon juice, and water to saucepan. Puree using an immersion blender until smooth. Alternatively, you can use a food processor. If soup seems too thick, add additional water. Adjust salt to taste.
Garnish soup with remaining raw zucchini, pine nuts, and lemon zest.