Place lemon juice, water, garlic, salt, and tahini in blender and blend until fairly smooth.
Add green onions and blend until onion is coarsely chopped.
Add fresh herbs and pulse until herbs are coarsely chopped. Set aside.
In a large skillet, sauté onion and summer squash in oil over medium (not high) heat until onion is translucent and squash is tender. (If squash isn’t tender when onions are ready, place lid on pan for one or two minutes to help squash cook.)
Add potatoes and sauté (uncovered) for two minutes.
Remove from heat and season with granulated onion and salt.
Serve vegetables with sauce for drizzling.
Notes
Yield: 2 servings as a main dish, 4 as a side dish