6 tablespoons EVOO – Extra Virgin Olive Oil, divided
3 medium (about 1 pound) yellow- or white-skinned potatoes, sliced 1/4-inch thick
Salt and pepper
4 cloves garlic, sliced
1 small onion, quartered and thinly sliced
2 firm zucchini, seeded (if necessary) and sliced 1/4-inch thick
2 tablespoons thyme, chopped
1 28-ounce can San Marzano tomatoes, crushed by hand
A few leaves of basil, torn
2 medium leeks, thin half moons
10 to 12 artichoke hearts from 2 boxes, defrosted, patted dry and sliced or if fresh, thinly sliced and dressed in lemon juice
1/4 cup parsley chopped
2 to 3 ribs celery with leafy tops, thinly sliced
1 quart chicken or vegetable stock
1 chunk rind Parmigiano-Reggiano, plus some to top soup
1/2 to 3/4 pound cremini mushrooms, sliced