Zucchini Casserole With Garlicky Breadcrumbs

Ingredients

• medium zucchini, sliced into ¼”-thick rounds
• medium Roma tomatoes, sliced into ¼”-thick rounds
• extra-virgin olive oil, divided
• Kosher salt, plus more for seasoning
• Freshly ground black pepper
• slices sourdough or whole wheat bread, cut into cubes
• c. freshly grated Parmesan
• Fresh oregano or thyme leaves
• garlic cloves, roughly chopped
• Crushed red pepper flakes