Preheat the oven to 350°. Prepare a 12 cup bundt pan by greasing with butter and dusting with flour. In the mixing bowl, beat the butter and sugar together until fluffy, about six minutes.
Scrape down the sides as needed. Add the eggs, one at a time, beating well between each addition and scraping down the sides as needed. Next, add the lemon juice and vanilla to the batter. Blend until mixed.
Add the flour a scoop at a time, alternating with the 7 Up soda. Scrape down the sides as needed. Transfer the batter to the prepared bundt pan, spreading evenly so it is the same thickness all the way around.
Bake for 65 to 75 minutes or until a toothpick inserted into the cake returns mostly clean with moist crumbs attached. Cool the cake in the Bundt pan on a wire rack for 15 minutes
Place a paper towel on top of pan with a plate on top that and use pot holders to grasp both sides. Flip upside down so it slides out. Allow the cake to cool.
Whisk together the ingredients for the glaze. Pour the glaze over the Bundt cake. Slice the cake and serve.