Preheat oven to 325F. with rack in lower third of oven. Grease and flour a 12-cup capacity/9 x 4 1/2-inch bundt or tube pan (with removable bottom, greasing the tube as well). Set aside.
Whisk together the flour, baking powder and salt. Set aside.
In a large bowl with an electric mixer or the bowl of a stand mixer fitted with a paddle attachment, cream the butter. Add the sugar and beat for 2-3 minutes, until light and fluffy. Beat in the eggs, one at a time, beating well after each addition, scraping down the sides of the bowl as needed. With mixer on lowest speed, add the dry ingredients in 3 additions, alternately with the milk in 2 additions, scraping the bowl as necessary. Beat only until smooth after each addition. Stir in lemon zest.
Spoon batter into prepared pan. Let top by rotating pan back and forth.
Bake for 70-75 minutes, or until a tester comes out dry.
For a bundt cake: Let cake stand in the pan for about 3 minutes, then cover with a rack and invert. Remove pan, leaving the cake upside down. For a tube pan, let stand 5 minutes, then run a knife around the outside and centre hole. Carefully push up from the bottom to remove cake from outside ring. Place onto cooling rack with the base still attached. Proceed to brush with glaze and cool, then remove from the base by running a knife underneath the cake and using two spatulas to lift the cake off the base of the pan.
Place a baking sheet under the cooling rack and prepare glaze by stirring together the glaze ingredients. (Glaze must be used immediately after it is mixed). Brush glaze liberally all over the hot cake until absorbed. Let cake cool completely. Do not cut for at least several hours.