h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

When I'm at home, I usually do jacket spuds in the microwave. Ours is a combination microwave - it can act like a conventional oven or as a microwave, or both. You get the best jackets using both!

For really crispy skins, wrap the potato in aluminum foil and put a pat of butter between the potato and the foil. Here's the trick, piece the potato with a fork, before the foil goes on.
The potato will release steam as the water it stores heats up, and the steam will help cook the butter to the skin. The trick is to not add too much butter, otherwise the spud gets mushy and you get mashed potatoes.

I forgot to mention, if the jacket isn't crispy enough, remove the foil and let the buttered jacket broil for a minute

For the best baked potato you should cook in the microwave, then put in a conventional oven for about 40 minutes to get the skin nice and crispy and the middle nice and soft. So there .