Why worry about the fat in a couple of grams of butter when you're eating all that cheese? OTOH sometimes I would make a fake grilled cheese just for the convenience of not needing to clean the skillet.. Two slices of toast, cheese in the middle then a short stint in the microwave to melt the cheese. A little spread/margarine enhances the flavor.
I was making waffles yesterday and had to melt butter for the batter. I put a stick in a open bowl in the microwave and hit 2 minutes for some reason (meant to grab it much sooner than than). Forgot about it and 1 minute in, the f'er exploded. Nothing was left in the bowl, just the whole inside of the microwave dripping in boiling butter.