Sour Cream Lemon Cupcakes

1 cup butter or margarine, softened
2 cups sugar
3 eggs
2 tsp. grated lemon zest
1 tsp. vanilla extract
3-1/2 cups all-purpose flour
1 tsp. baking soda
1/2 tsp. each baking powder, salt
2 cups sour cream
Frosting:
9 tbsp. butter or margarine, softened
6-3/4 cups confectioners' sugar
6 tbsp. lemon juice
1 tbsp. vanilla extract
3/4 tsp. grated lemon zest
3 tbsp. milk 

 

      Heat oven to 350ºF (175ºC).  In a mixing bowl, cream butter and sugar.  Beat in eggs, 1 at a time.  Add lemon zest and vanilla; mix well.  Combine dry ingredients; add to creamed mixture, alternately with sour cream (batter will be thick).  Fill 30 greased or paper-lined muffin cups with 1/4 cup batter.  Bake 25 - 30 minutes, until a pick inserted near center comes out clean.  Cool 10 minutes; remove to wire racks, cool completely. 
Frosting:  Cream butter and sugar in a small mixing bowl.  Add lemon juice, vanilla, lemon zest and milk; beat until smooth.  Frost cupcakes.  Makes 30 cupcakes.