In a large mixing bowl, whisk together the dressing ingredients: extra-virgin olive oil, red wine vinegar, minced garlic, and Dijon mustard. Season with kosher salt and black pepper to taste.

Preheat the oven to 400°F (200°C). Spread stale bread cubes on a baking sheet, drizzle with olive oil, and sprinkle with flaky sea salt. Toast in the oven for about 10 minutes or until golden brown and crisp.

Once the toasted bread has cooled, add it to the dressing in the mixing bowl. Toss well to soak the bread in the dressing. Add chopped tomatoes, diced peaches, and minced chives. Mix gently to combine.

Transfer to a serving plate, tear buffalo mozzarella into pieces and scatter on top. Garnish with fresh basil leaves. Optionally, add sliced salami or prosciutto. Drizzle with extra olive oil and adjust seasoning before serving.