Caramelized Onion Mashed Potatoes with butter

2 lbs russet potatoes , peeled and cut into chunks 1/3 cup half-and-half 2 tablespoons butter 1 -2 tablespoon coarse grain mustard 1/4-1/2 cup caramelized[...]

3 lbs yukon gold potatoes , peeled and quartered 1 3/4 teaspoons salt , divided 2 tablespoons butter or 2 tablespoons margarine 1 tablespoon olive oil 2[...]