White chocolate baking in cake batter
Should you chop up the white chocolate baking bar and fold it into the batter, it will behave like any chip in a batter, melting slightly and leaving little surprises throughout. If you wish to incorporate into the cake, melt it either over a double boiler or very carefully in the microwave (checking every 10 seconds), and let it cool. After following your vanilla cake recipe (creaming butter and sugar, adding eggs, flour, milk), stir in the cooled white chocolate and mix completely. You could amp up the white chocolate effect by adding melted white chocolate to the frosting and topping with white chocolate shards or curls.