In a bowl, mix together the first 3 ingredients; stirring well.
Sprinkle in a greased and floured 10-inch tube pan; set aside.
Cream butter in a large mixing bowl; gradually add 1 cup sugar; beating with an electric mixer on medium speed.
Add eggs one at a time; beat well after each addition.
In another bowl, mix together the flour, baking powder, soda, and salt; add to the creamed mixture alternately with the yogurt (begin and end with flour mixture); mix just until blended after each addition.
Stir in 2 teaspoons lemon rind and vanilla.
Pour batter into prepared tube pan.
Bake in a 350° oven for 50 minutes or until pick comes out clean.
Cool in pan for 10 minutes; turn out of pan and cool completely, sugar-nut side up, on a wire rack.
In a saucepan, mix together the lemon juice and 1/2 cup sugar; bring to a boil; stir until sugar dissolves.
Pour hot glaze over cake. (You can poke holes in top of cake with a toothpick so the glaze will seep down into the cake if desired).