In a large soup pot, sauté onions in oil over medium (not high) heat for 5 minutes. Onions should not brown; they should just begin to turn translucent.
Meanwhile, place cashews, 1 cup water, granulated onion, and salt, in blender and blend until very smooth. (A heavy-duty blender works best for this recipe; other blenders may not get the mixture smooth enough.) Set aside.
Add zucchini and summer squash to soup pot and continue to sauté for 3 minutes.
Add garlic and potatoes and sauté for one additional minute.
Pour remaining 2 cups water into pot and turn heat to high.
Stir in herbs and kale.
Cover pot and bring to boil. Reduce heat and simmer until potatoes are tender, about 6 to 8 minutes.
Stir in blender mixture. Serve hot.
Notes
I like to sprinkle some Herbamare in this soup before serving.