A method of forming a component having an internal passage defined therein includes forming a precursor core having a shape corresponding to a shape of the internal passage, and forming a hollow structure around the precursor core. The method also includes removing the precursor core from within the hollow structure, and disposing an inner core within the hollow structure to form a jacketed core. The method further includes positioning the jacketed core with respect to a mold, and introducing a component material in a molten state into a cavity of the mold, such that the component material in the molten state at least partially absorbs the hollow structure from a portion of the jacketed core within the cavity. Additionally, the method includes cooling the component material in the cavity to form the component. The inner core defines the internal passage within the component.