How to Make It
Bring a large pot of salted water to a boil. In a large bowl, toss the onion with the anchovies and vinegar.
Add the potatoes to the boiling water and cook for 5 minutes. Add the beans and cook for 5 minutes, then add the zucchini and yellow squash and cook for 5 minutes longer. Drain the vegetables very well in a colander.
Stir the olive oil, basil and garlic into the onion mixture in the bowl. Gently fold in the vegetables, allowing the potatoes to break up slightly and coat the vegetables. Season with salt and pepper and serve warm or at room temperature.