Heat oven to 325°F. Spread sugar evenly over bottom of heavy skillet. Cook over medium heat, stirring constantly, until sugar melts and turns light caramel color. Add 3 tablespoons boiling water, stirring until sugar is dissolved. Pour into ungreased quiche dish or 10-inch glass deep-dish pie pan or 8-inch (2-quart) square baking dish . Tilt to evenly cover bottom; set aside.