this is cream cheese frosting elevated for the kings, recipe at ROSE’S heavenly CAKES: Rose Red Velvet Cake (page 83). this frosting makes beautiful rosettes, specially when using a polycarbonate piping tip.
my method is a little different since i prefer to use a blender instead of a food processor. be aware that my blender is 800 rpm. here are the progress photos: using the microwave to melt white chocolate together with butter, pausing frequently to stir until the glass bowl feels cool to the touch (the melting takes place while hand stirring and not while microwaving), using my infrared thermometer to check temperature, blending at 800 rpm, checking temperature, adding the rest of ingredients.