D'best Cheesecake

In small bowl with mixer at low speed, beat butter, 1 1/4 cups flour, 1/4 cup sugar, 1 egg yolk and half of the lemon peel until dough is well mixed. Refrigerate, covered, for 1 hour. Preheat oven to 400-degrees. Press 1/3 of dough into bottom of 10-inch spring form pan. Bake 8 minutes; allow to cool. Turn oven to 475-degrees. In large bowl with mixer at medium speed, beat cream cheese just until smooth; slowly beat in 1 3/4 cups sugar until smooth. With mixer at low speed, beat in 3 T flour and remaining ingredients. except sour cream. At high speed beat 5 minutes. Press rest of dough around side of spring form pan to within 1-inch of top, do not bake now. Pour cheese mixture into pan; bake 12 minutes. Turn oven to 300-degrees; bake 35 minutes. Turn off oven; leave in oven 30 minutes. remove; cool in pan on rack. Chill. To serve: Remove side of pan. With large spatula, loosen cake from plate. Spread top of cheesecake with sour cream to garnish.