Lemon Oatmeal Cookies

1 C butter, softened
2 C sugar
2 large eggs, room temperature
2 tsp grated lemon zest
3 T lemon juice
2-3/4 C all-purpose flour
1 C quick-cooking oats
2 tsp baking powder
1/4 tsp salt
Additional sugar

In a large bowl, cream butter and sugar until light and fluffy. Beat in eggs, lemon zest, and lemon juice. In another bowl, whisk flour, oats, baking powder, and salt; gradually beat into creamed mixture. Refrigerate, covered, two hours or until firm enough to shape.  Preheat oven to 375 degrees. Shape level tablespoons of dough into balls; place two inches apart on parchment-lined baking sheets. Coat bottom of a glass with cooking spray, then dip in sugar. Press cookies with bottom of glass to flatten, re-dipping in sugar as needed.  Bake until edges are light brown, six to eight minutes. Remove from pans to wire racks to cool.