Homemade Baking Powder (single acting)
           2 measure cream of tarter
           1 measure baking soda
      Mix together and use immediately.
      If you want to mix ahead of time and store no longer
      than one month, add 1 measure cornstarch
 Note:  I use teaspoons for measure amount, but it really depends on how much
 you need.  The cornstarch will help keep the other ingredients from absorbing
 moisture (this is what is used in manufactured baking powder).  If you have a
 recipe that calls for double acting baking powder, just use twice the amount.
 Oh, one more thing, to check and see if the baking powder in your pantry is
 still active, stir 1 teaspoon into one-third cup hot water.  There should be
 immediate vigorous bubbling.  If no bubbling or bubbling is sporadic, the
 baking powder is past its prime.  
 Homemade baking powder starts to fizz and release carbon dioxide the minute
 it is added to liquid, it is very important that the oven be preheated and
 baking pans be ready before mixing batter.  Mix quickly and put in oven right