Drizzle the zucchini, eggplant, red pepper and scallions with olive oil and a few pinches of salt. Grill until charred, about 3 minutes per side.
Remove the vegetables from the grill, let cool slightly, then chop everything into 1-inch pieces. Toss them in a mixing bowl with the cherry tomatoes, garlic, sherry vinegar, herbs de Provence and basil.
Season to taste, then serve on toasted bread with a spread of goat cheese or hummus.