Before melting white chocolate, it is helpful to become familiar with the Tips for Melting Chocolate chapter.
When ready to melt white chocolate for truffles, use a microwavable or oven-proof bowl (depending on your melting method). The bowl needs to be large enough to accomodate stirring together the white chocolate and cream cheese.
Measure white chocolate chips or pieces into the bowl.
Melt and stir the chocolate only enough so all clumps and pieces have been dissolved. The chocolate needs to be fully dissolved. If tiny (or larger) partially solid pieces remain, they are likely to be visible as white spots within the truffle candy center, especially if it is a colored center.
The melted white chocolate is now ready for the rest of the truffle ingredients.