2 teaspoons olive oil
1 pound parsnips, peeled and coarsely chopped
1 small celery root, peeled and sliced 1/3 inch thick
2 medium carrots, thinly sliced
1 medium red potato, cut into 1-inch dice
1 large leek, white and tender green, thinly sliced
2 garlic cloves, minced
3 fresh thyme sprigs
Salt
1 quart chicken stock or canned low-sodium broth, defatted
Freshly ground pepper
1 tablespoon minced fresh rosemary