Bring a large pot of salted water to a boil for the pasta. Cook according to package instructions, being careful not to over-cook. I use gluten-free pasta and slightly undercook the pasta to ensure it doesn't fall apart.
Preheat the oven to 425F. Chop the zucchini, yellow squash, and bell pepper. Cube the sourdough bread.
When the pasta is done cooking, drain and add to a large bowl. Drizzle and stir with a tablespoon of olive oil to prevent the noodles from sticking together.
Add a tablespoon of olive oil to a medium frying pan and heat over medium. Once warm, add the zucchini, squash, and bell pepper, along with the salt and pepper. Sauté until the veggies are soft and the zucchini and squash are translucent.
Combine the cubed sourdough with olive oil, garlic powder, salt, and pepper. Spread out onto a baking sheet and bake for about 15 minutes. Oven temperatures vary, so check periodically to make sure the croutons don't burn.
To the large bowl with the pasta, add the sun-dried tomatoes, olives, capers, basil, and the sautéed veggies. When the croutons are done, add them to the bowl (check the notes for exceptions!). Add balsamic vinegar, starting with 2 tablespoons and adding more if desired. Then garnish with freshly ground black pepper. Make sure everything is well-combined and taste to make sure each bite is bursting with flavor, adding more oil, vinegar, salt, or pepper if needed.