Ingredients 2 tablespoons extra-virgin olive oil, plus more for drizzling 1 cup chopped onion or other allium (leeks, shallots, scallions) 1 tablespoon minced garlic (from 3 cloves) 3/4 cup diced carrot 1/2 cup diced celery Kosher salt 1 teaspoon dried oregano or thyme (or 2 to 3 sprigs fresh), optional 1 tablespoon tomato paste, optional 1 Parmesan rind (optional), plus finely grated Parmesan for serving 2 cups peeled and diced hard, starchy vegetables, such as potatoes, parsnips, turnips, or squashes 8 cups low-sodium chicken or vegetable broth, or water 1 to 2 cups quick-cooking vegetables cut into bite-size pieces, such as green beans, broccoli, zucchini, peas, and/or corn 1 cup cooked rice, pasta, or canned chickpeas or other beans or legumes 1 to 2 cups chopped leafy greens, such as spinach, arugula, kale, or Swiss chard Fresh herbs, such as flat-leaf parsley or basil, for serving Simple Crostini, for serving...