Cut bread into 1-inch cubes. Place on a baking sheet, drizzle with some of the olive oil and all of the butter, sprinkle with some of the salt and pepper, toss, and bake at 400 F for 10 to 15 minutes, until toasted. Transfer bread to large serving bowl.
Turn oven up to 450 F. Toss tomato halves with some of the olive oil, salt, pepper, and sumac and spread out in a single layer, flesh side up, on the same baking sheet. Roast for 15 to 20 minutes or until tomatoes are tender.
Toss cubed eggplant in a bowl with olive oil, salt, pepper, and sumac. Spread out on a separate baking sheet lined with parchment paper and roast for 30 minutes, stirring halfway through.
Mix dressing ingredients (olive oil, red wine vinegar, capers, sumac, Italian seasoning) together with an immersion blender to break up the capers. Add roasted tomatoes and eggplant to the bowl with the bread, along with the olives and mozzarella. Generously drizzle with dressing and serve warm or at room temperature.
Note: Italian, French, or focaccia bread can be substituted.
Per serving: 557 calories, 34 grams fat (9 grams saturated fat), 31 milligrams cholesterol, 1,234 milligrams sodium, 47 grams total carbohydrates, 7 grams fiber, 17.5 grams protein.
