Heat butter in a Dutch oven over medium heat until foaming has subsided. Add the onion bulb and zucchini, along with 1 teaspoon sea salt and pepper to taste, and cook, stirring occasionally, until softened and just lightly browned, about 10 minutes. Add the garlic and cook, stirring often, until fragrant, about 1 minute. Add the stock and bay leaf, cover, and bring to a simmer and cook for 10 minutes. Remove the cover and add the onion greens and peas and simmer for another 2-3 minutes, or until the onion greens are just soft. Remove from heat, add fresh herbs (start with 1 tablespoon) and puree using an immersion blender (easier but you won't get a really smooth texture) or transfer to a blender in a couple batches (more time consuming but you get a smoother texture). Taste and adjust seasoning as needed, adding the additional tablespoon of herbs if desired. Serve immediately or cool to room temperature before storing in an air-tight container in the refrigerator. Garnish ideas are listed above in the "Variation" section.
1) you can serve this hot, room temperature or chilled, making it a great soup for any time of year; 2) I used parsley as the fresh herb addition when I garnished it with creme fraiche and then cilantro when I garnished it with tempeh, but I think basil or tarragon would be great as well.