Preheat the oven to 325°F. In a stand mixer bowl, beat together the butter and sugar on medium-high speed until the mixture becomes pale and fluffy, which should take around 12 to 13 minutes. Incorporate the eggs one by one, ensuring each is fully mixed before adding the next. Slowly blend in the flour along with the lemon zest, stirring only until the ingredients are uniformly combined. Gently fold in the 7UP soda to complete the batter.

Transfer the batter into a thoroughly greased Bundt cake pan, spreading it evenly. Bake in the preheated oven for 70 to 80 minutes, or until a toothpick inserted in the center emerges clean. Allow the cake to rest in the pan for 15 to 20 minutes before inverting it onto a wire rack to cool entirely.

To prepare the glaze, whisk the powdered sugar and lemon juice together until smooth. Adjust the consistency by adding lemon juice one teaspoon at a time if needed for a drizzle-friendly texture. Conversely, add a touch more powdered sugar if the glaze is overly runny. Drizzle over the fully cooled cake.