A white hot chocolate, as the name suggests, is the same as a normal
hot chocolate only white chocolate is used in lieu of dark or milk chocolate. White chocolate powder can be sourced to create the base otherwise melting white chocolate down into a sauce will also work.
Then water, or more commonly, textured milk can be added and topped with froth or whipped cream. Chocolate sprinkles or shavings make a nice finish to top the white foam.