There are several causes for fallen cakes, Darlene. They are:

1. The cake is baking too slowly due to the oven temperature being set too low or because the pans were put in the oven before the oven was finished preheating. Use an oven thermometer to make sure the thermostat is accurate and the oven is reaching the set temperature. Preheat the oven for at least 15 to 20 minutes before setting the pans inside it.

2. Either overbeating or underbeating, so that there is either too much or too little air in the batter.

3. Underbaking. Set your timer for the shortest recommended time in the recipe. Check doneness by inserting a wooden pick into the center; there should be only a few crumbs on the pick. If there is batter, continue baking up to the longest recommended time. Test again and continue baking if still not done.

4. There may be either too much or too little liquid in the batter, or too much sugar. Make sure your measurements are accurate.

5. Moving the cake during the middle of the baking time, before it's set. My mom always warned me not to jump or stomp on the kitchen floor while she had a cake in the oven, so that it wouldn't fall. Opening the oven door during this crucial time can also make it fall.

6. Cake pan is too small for the amount of batter.

7. Too much baking powder or baking soda. Again, measure accurately.