Heat oven to 325 degrees F.  Grease and flour Bundt pan.  In large bowl, cream butter and sugar until light and fluffy.  Add beaten egg yolks until incorporated.  Sift together flour, baking powder and salt.  Re-sift 3 times.  Add to butter mixture, alternating with milk.  Mix until incorporated.  Add vanilla, lemon peel and lemon juice.  Beat 2 minutes.  Bake for one hour, or until cake tester comes out clean.  Cool cake in pan 10 minutes.  Invert onto serving platter to complete cooling.  Sprinkle with confectioner’s sugar, if desired.