Heat oven to 350°F. Generously spray 12-cup fluted tube cake pan with cooking spray. In large bowl, beat 2 cups sugar and 1 cup butter with electric mixer on medium speed until light and fluffy, scraping bowl occasionally. Add 1 egg at a time, beating well after each addition. Stir in lemon peel.
On low speed, beat in flour, baking powder, salt, baking soda and milk until smooth, scraping bowl occasionally. Pour batter into pan.
Bake 50 to 60 minutes or until toothpick inserted near center comes out clean. Cool in pan 15 minutes. Place heatproof serving plate upside down over pan; turn plate and pan over. Remove pan.
Meanwhile, in 1-quart nonaluminum saucepan, heat glaze ingredients over medium heat, stirring occasionally, until butter is melted.
With long-tined fork or skewer, generously prick top and sides of cake. Brush warm glaze over cake, allowing glaze to soak into cake. Cool completely, about 1 hour 30 minutes, before serving. Garnish with powdered sugar and edible flowers, if desired.