Sour Cream Cookies

My friend Teri makes these really yummy, fluffy, moist, amazing sour cream cookies. I've made them a couple of times and while they taste just like hers, they NEVER puff up like hers do. I don't know what I'm doing wrong, but I bought the ingredients again and will make them AGAIN later this week to see if I can get them puffy-fluffy so you can see how they are supposed to look.

Sour Cream Cookies

Mix together thoroughly:
½ C. Soft Shortening
1 ½ C. Sugar
2 Eggs

Stir in:
1 C. Thick Sour Cream
1 tsp Vanilla (I usually add a little almond as well)

Sift together and stir in:
2 ¾ C. Flour
½ tsp Baking Soda
½ tsp Baking Powder
½ tsp Salt

Chill at least one hour. Drop by tsp on un-greased cookie sheet. Bake until just lightly brown or when touched by a finger only a slight imprint remains.
Bake 8 to 10 minutes at 400°.