The flavor of this soup will knock your socks off! And it’s had with such ease, owing to the basil being added at the very end, after the soup is cooked…a very simple soup to eat any day of the week, and good enough to serve at an elegant dinner party. The recipe is adapted from Patricia Wells’ The French Kitchen Cookbook.
In a stock pot or 8-quart pot, heat the olive oil over low heat until it is hot but not smoking. Add the sliced onions and sprinkle with a pinch of salt. Saute the onions for about 8 minutes, or until they are soft and translucent, but not browned, covering them and stirring occasionally.
Add the zucchini to the pot along with the chicken or vegetable stock and season with a pinch of salt and a few grinds of black pepper. Cover and cook for about 10 minutes, or until the zucchini is softened.
Remove the soup from the heat and allow it to cool, uncovered, for at least 15 minutes, stirring occasionally to release steam. Stir in the fresh basil leaves just before pureeing. In a blender, puree the soup in batches and return to a smaller, clean pot (a 3- to 4-quart pot). Or, use an immersion blender to puree the soup in its pot.
Taste and add more salt and pepper, if needed. Serve the soup heated through, room temperature, or chilled.