A good friend of mine named Dana turned me onto this, and it's a really fun idea, I use it to send homemade cakes to the Soldier's Jon serves with. It's important to use the WIDE STRAIGHT ( added pics of the difference between the ones you need and the ones that won't work.lol..cuase I know..I tried..lol, so use the one on the LEFT) mouth canning jars to ensure the cake can come straight out. Just preheat your oven to 350, grease the inside of the jar with crisco, not pam. Pour in appox. 1 cup cake mix. Some times you have to experiament with that. Some times a certian cake mix only takes 3/4 a cup others needs 1 cup and two tblsps. You want the cake to rise ALMOST to the top, not above the rings, so that it doesn't interfer with the lid sealing. I do four jars at a time, to ensure I get at least one or two good ones when I am fiddleing with how much mix I put in. Place them on a baking sheet to keep the level in the oven and bake for about 30 mins. I check mine around 25 with a toothpick.. if it's done on top use a butter knife all the way down into the bottom to see if thebottom half is done. If it's not, cover the top with foil loosely and bake another 5-10 minutes. While it's baking, boil the lids. As soon as you pull out the cakes set them on a rack to cool with out moving them too much and immdiatly place on the lids after you dry them completly. Let them seal and cool. It make sure they are sealed or by the time you send them to Iraq they will get moldy. Sealed it can last up to 6 months I am told, I only know for certian that 2 months works since thats the longest I have had one in the cabinet without my kids eating it..lol. Let me know how it goes! If you have questions give me a call! It's a fun surprise! I send a jar of frosting along with it, and a paper plate and silverware, a candle that when you twist the bottom plays happy birthday.