Irish Lemon Pudding

1.Preheat oven to 350 degrees. Spray a 8-inch cake pan with cooking spray.
2.In a large bowl, cream the butter and sugar well. Add the egg yolks one by one, mixing after each addition. Add the flour, lemon zest, lemon juice, then followed by the milk, and mix well.
3.In a separate bowl, whisk the egg whites until stiff. Fold gently into the lemon mixture until incorporated. Pour batter into prepared cake pan and smooth out the top.
4.Bake for 40 minutes, or until very lightly browned and set. Sprinkle with powdered sugar and serve warm with freshly whipped cream.