Place jars evenly spaced on a cookie sheet. While cakes are baking, bring a saucepan of water to a boil and carefully add jar lids. Remove pan from heat and keep hot until ready to use. Remove jars from oven one at a time keeping remaining jars in oven. Make sure jar rims are clean.
Place lids on jars and screw rings on tightly.
Jars will seal as they cool. Cakes will slide right out when ready to serve.