My oven cooks unevenly
One solution is to use a baking stone.  There are lots of variations available, from thick ceramic baking trays to pizza stones to bit of tile or stone scavenged from contractors or construction people.  The point is, the (well cleaned) stone goes in your oven, and stays there.  It takes more time to heat up, and also to cool down - but in exchange for this the temperature is more consistent since it takes longer to change.

People use them to avoid or lessen the effects of the kind of cyclic heating ovens normally use (heats up until it senses the temperature, stops heating until it cools enough to trigger the sensor, heats again) a style of heating which means oven temperature is usually a wobbly average, not an absolute temperature.  The stone also helps lessen the effect of hot-spots and areas, since the heating element preheating the stone, lets the stone be used as a sort of secondary heat-distributor... one which collects and distributes the heat more evenly, since it doesn't have the same hot-spots as the original element.  Hot spots from the top element might still happen, but the stone helps.

In your case, the heating element on the bottom would have to be buffered through the heating stone to reach the food - so the whole stone would heat more slowly, and more heat would cook the rest of the food instead of just getting the bottom burned.

Some dishes which use a shorter cooking time will cook a little differently, since being in contact with the hot stone means they will heat up a little faster (cookies, for example) - but it usually isn't a big problem, and dishes which cook longer will have time to even the heat back out.