Cream butter and sugar together. Add eggs and beat until light and fluffy. Sift together flour and soda; add alternately to the creamed mixture with 1/2 cup of the lemonade concentrate. Drop dough from a teaspoon 2 inches apart onto ungreased cookie sheet. Bake cookies in a hot oven at 400 degrees F for about 8 minutes or until lightly browned around the edges. Brush hot cookies lightly with remaining lemonade concentrate. Sprinkle with granulated sugar. Remove cookies to cooling rack.