In a large pot, heat the oil over medium-high heat. Add the garlic and onions
and cook, stirring, until the vegetables soften, 3 to 5 minutes. Add the eggplant
, yellow squash and zucchini
, and season with salt and pepper. Cook, stirring frequently, 5 more minutes. Stir in the basil
and cook 1 more minute. Stir in the tomatoes (with their juices) and chicken broth and bring to a boil. Reduce the heat and simmer
10 minutes to allow the flavors to develop.
Remove from the heat and cool slightly. Garnish with chopped basil and serve with Garlic Crostini.