The best chocolate for cooking is dark cooking chocolate containing a high percentage of cocoa solids. Milk chocolate is rarely used in cooking as it does not have the depth of flavor of dark chocolate, but it can be used if it is chilled and then finely grated before melting. These steps are necessary because milk chocolate can easily seize up.
'Chocolate compound' cake coverings or coatings are not chocolate at all. They contain no cocoa solids and most or all of the cocoa butter has been replaced with coconut or palm oil. Although they are very easy to melt and handle, these coatings do not have the flavor or texture of real chcolate. It is a false economy to cook with very inexpensive chocolate or substitutes as the results are disappointing.
** Asian Online Recipes