Use
only wide-mouth jars. Filling the jars can be tricky because you want
the cakes to bake to within one-quarter to one-half inch of the rim.
Make one test cake by filling one jar halfway to ensure you have the
right time and temperature. Do this at higher altitudes, too.
For
half-pint jars, use one-half cup batter and bake at 325*F for about 30
minutes. For pint jars, use 1 cup batter and bake at 325*F for 55 to
60 minutes. For 1-1/2-pint jars, try 1-3/4 cups batter and bake an
hour or longer at 300*F. A long cake tester is useful to verify
doneness.
Make
sure there are no nicks or cracks on the lips of the canning jars.
Wash jars, lids and rings in hot soapy water, then sterilize by
boiling them for 15 minutes. The lids and rings are kept in hot water
until you're ready to use them, but the jars are moved from the water
and placed on a towel to air dry while you mix the batter.
The
jars must be well greased with shortening or oil so the cake will
slide out. After the cakes are done, you take them out of the oven,
one by one, and put the lids and rings on them. Screw the lid tightly.
As they cool on a bath towel on your counter, you should hear a
"plink" sound indicating that they have sealed. If you don't
hear it, check cooled jars by pressing down on the lid. It shouldn't
move at all.
Refrigerate
unsealed cakes or freeze them. Sealed cakes will keep in a cool, dry
place for about six months. You can send one with a candle as a
birthday cake.
