Besides, contrary to the 'Urban Legend':
Microwaves DO NOT cook from the inside out.
If an item bein microwaved is of uniform consistency and high in water content, most of the microwave energy will be absorbed by the water near the surface before it gets into the center of the item, and the food will heat from the outside in, as with traditional ovens. On the other hand, if the surface of the item is drier than the center, as with bread or a baked potato, the center will heat up faster. You can see this clearly if you microwave foods with a dry outer crust and a moist filling, like a McDonald's apple pie. If you cook it for about 20 seconds in a typical oven, you'll find that the crust is fairly cool to warm, while the filling can be quite hot. "
Edited food to 'item' but it's a quote from:
http://www.straightdope.com/columns/read/2118/do-microwave-ovens-cook-from-the-inside-out
In the simplest terms Microwaves create heat almost entirely by spinning water molecules (because water molecules are polar, that is they have a positive and negatively charged pole that the microwave radiation can 'grab onto' and 'spin' the molecule.
IF there are no molecules of water preset, the microwaves effectively are without the ability to 'cook' at all.
So, no water, no heat. If the center has more water than the outside, you may notice that the center is hotter and hence, incorrectly attribute it to cooking from the 'inside-out'. Were the object reversed and dry on the inside and wet on the ouside you would notice the exact opposite effect. The simple fact of the matter is, there are few foods that are dry on the inside and wet on te outside, so we see the oppsite behavior so rarely that this incorrect idea has flourished.