Root Vegetable Gratin

Name: Root Vegetable Gratin
Ingredients: • 2 1/2 cups heavy cream; • 2 teaspoons kosher salt; • 1/2 teaspoon freshly ground nutmeg; • 3 large russet potatoes, peeled and thinly sliced; •2 large carrots or 1 sweet potatoe, peeled and thinly sliced; • 2 medium parsnips, peeled, trimmed, and thinly sliced; • 1 large shallot, thinly sliced; • 2 garlic cloves, unpeeled, crushed; • 1 medium celery root, peeled, halved, and thinly sliced; • 8 ounces Gruyere or good Italian Fontina cheese, coarsely shredded; • 3 sprigs fresh thyme; 1/2 teaspoon freshly ground black or white pepper