In the bowl of a stand mixer, cream together butter and sugar until light and fluffy (about 12-13 minutes). Add eggs, one at a time, beating after each one. Gradually add flour and lemon zest, mixing just until everything is combined. Fold in 7-Up.
Bake for 70-80 minutes (or until a toothpick inserted in the center comes out clean). Cool in the pan for about 15-20 minutes, and then remove to a wire rack to cool completely.
Once the cake is cool, prepare the glaze by whisking together the powdered sugar and lemon juice until smooth. Add extra lemon juice (1 teaspoon at a time), just until the glaze is thin enough to drizzle over the cake. If the glaze is too thin, add a little bit of powdered sugar until it reaches the desired consistency. Drizzle glaze over cake.
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Notes
When zesting the lemons,you only want to scrape off the very outer peel. This is where all of the essential oils and flavor can be found. You do not want to scrape off the white pith, which has a bitter taste.
Make sure that youspray your Bundt pan really well with cooking spray, or grease with butter and sprinkle with flour. This will prevent the cake from sticking to the pan.
Properly measure the flour. Weigh the flour on a kitchen scale or spoon the flour into the cup and lightly level with the straight edge of a knife. Packing the measuring cup too tightly and using too much flour will result in a dry cake.
Make sure that all of your ingredients are at room temperature so that they blend together smoothly.
Cream the butter and sugar until the mixture is light and fluffy, about 12-13 minutes. Whipping this air into the batter will help the cake rise during baking.
Don't leave the cake in the pan for too long after baking -- about 10-15 minutes is plenty. After that, condensation will start to form and the moisture will negatively impact the crust.