Preheat & Prepare Pan: Preheat oven to 325°F (165°C). Grease and flour a 10-12 cup Bundt pan or a 9-inch tube pan thoroughly.

Combine Dry Ingredients: In a large mixing bowl, combine the cake mix and instant pudding mix (if using).

Add Wet Ingredients: Add the eggs, oil, 1 cup of 7UP soda, and vanilla extract (if using) to the dry ingredients.

Mix Batter: Beat with an electric mixer on low speed for about 30 seconds to combine, then increase to medium speed and beat for 2 minutes, scraping down the sides of the bowl as needed. The batter will be smooth.

Pour & Bake: Pour the batter evenly into the prepared Bundt pan.

Bake for 60-75 minutes, or until a wooden skewer or toothpick inserted into the center of the cake comes out clean.

Cool Cake: Let the cake cool in the pan on a wire rack for 10-15 minutes. Then, carefully invert the cake onto the wire rack to cool completely.

Make Glaze (Optional): Once the cake is completely cool, whisk together the powdered sugar and 1-2 tablespoons of 7UP or lemon juice until you reach a desired drizzling consistency. Add more liquid a little at a time if needed.

Glaze Cake: Drizzle the glaze over the cooled cake. Let the glaze set before slicing and serving.