Mashed Potatoes with chive

2 tablespoons unsalted butter 4 ounces carrots (parsnips, turnips, or celery root, peeled, carrots or parsnips cut into 1/4-inch-thick half-moons, t) 3/4 lb[...]

1/2 lb celery root , peeled and cut into 1-inch chunks 1 large baking potato , peeled and cut in half 1 garlic clove , peeled 2 tablespoons milk 1 tablespoon[...]

3 lbs yukon gold potatoes , peeled and cut into 2-inch pieces 1 lb celery root , peeled and cut into 2-inch pieces 2 garlic cloves , sliced 1 cup light cream[...]