To make a white-chocolate custard I have been melting chopped white chocolate (from a Ghirardelli bar) in a double boiler, then stirring a portion of a heated cornstarch-thickened milk custard base into it and then scraping this mixture back into the pot of heated custard base (hope that's clear). Do I have to use this many steps to avoid either scorching or seizing the white chocolate? can I just stir the chopped chocolate directly into the heated and thickened milk-cornstarch base without all the back-and-forth? Can I just dump scalded milk over it to melt it prior to thickening the whole with cornstarch? thanks.