does your recipe have cream of tarter or butermilk in it? or maybe it doesnt have enough?
Baking powder is more or less 2 parts baking soda, 1 part cream of tartar. it is a leaving agent on its own. Baking soda, need the acidy to 'jump start' it (similar to the volcano science experiment, you need an acid to make the baking soda work.
some info on spreading
sugar - high sugar content increases spread. coarse granulated sugar increases spread, while fine sugar or confectioners sugar reduces spread.
leavening - high baking soda content causes spread
Creaming - the craming together of fat and sugar contributes to leavening by incorperating air. Creaming a mixture until light increases spread. Blending fat and sugar just til a paste without creaming in alot of air reduces spread.
Temperature - Low oven temperature increases spread. High temperature reduces spread, because the cookie has a chance to set up before it spreads too much
Liquid - A high liquid content butter spreads more
Flour - strong flour (bread and clear flours) or activation of gluten decreases spread.
Pan grease - cookie spread more on a heavily greased pan.
stacey <- took the last part (spreading) from one of my text books