Preheat oven to 375 degrees.

Cream butter and sugar, add poppy seeds, and yogurt. Beat in 4 egg yolks Add dry ingredients. Fold in egg whites beaten to stiff peak in separate bowl. Pour batter into a greased 10" tube pan with removable bottom. Bake for 45 minutes. Remove from oven and cool in pan for 5 minutes. Then remove and invert on a rack to complete cooling.

Serving Suggestions:
When ready to serve, drizzle on a glaze of lemon juice, rind, powdered sugar and cream. Garnish with lemon slices and rind.