• Preheat your oven to 350°F.

  Generously spray a 12-15 cup bundt pan with non-stick baking spray. Alternatively, you can grease with shortening and lightly flour the pan.

Combine the Dry Ingredients

• Into a medium size mixing bowl, sift the all-purpose flour and baking powder. Repeat the sifting of the dry ingredients twice more.

  Set the bowl of dry ingredients aside.
• Into a separate, smaller bowl, crack the eggs and add the vanilla.

  Don't whisk the eggs. Set this bowl aside while you beat the butter and sugar.

Cream the Butter and Sugar

• In the bowl of a stand mixer combine the butter, sugar, salt, and 1 1/2 teaspoons of zest from the lemon and the lime (reserve the remaining zest for the glaze).

  Use the paddle attachment to cream the butter and sugar together on medium speed for 3 minutes. Stop the mixer and use a rubber spatula to scrape down the bowl and paddle.  
• Continue to beat the sugar and butter together on medium speed for an additional 3 minutes, or until the mixture is light, nearly white in appearance, and fluffy. 

Add the Eggs and Vanilla

• Decrease your mixing speed to low and add the eggs to the butter-sugar mixture, one at a time.

  Allow the mixer to blend the egg into the butter mixture before stopping the mixer and scraping the paddle and bowl down.
• Resume the mixing (on low), then add the next egg.

  Continue adding the eggs in this way until all have been added. Stop the mixer and scrape down the paddle and bowl once more. 

Alternate Adding the Dry and Liquid Ingredients

• In a bowl, gently stir together the sour cream, the 1/2 cup of 7up, and 2 tablespoons each of the lemon and lime juice. Set this aside.
• Add the dry and wet ingredients in stages: begin with the mixer on low speed and slowly mix in 1/3 of the dry ingredients.

  As soon as the flour is no longer visible, stop the mixer and scrape down the paddle and bowl.
• Now add 1/2 of the sour cream-soda mixture to the bowl. Mix just until the liquid is incorporated and add the next 1/3 of the dry mixture.

  Stop the mixer and scrape down the paddle and bowl as soon as the flour has been mixed in.
• Add the last of the wet, followed by the last of the dry, blending on the lowest speed just until the addition has been incorporated.

  Once the last of the dry mix has been added, only mix on low for 30 more seconds. Stop the mixer and use a rubber spatula to fold the batter a few times.

Bake the Cake

• Scrape the batter out of the bowl (and off of the paddle) into a lightly greased and floured bundt pan.

  Smooth the surface of the batter, give the pan a few gentle taps against the countertop to expels any air bubbles, and bake for 1- 1 hour 15 minutes in a preheated 350°F oven. 
• Once the cake has finished baking, place the pan on a wire rack over a sheet pan. Allow the cake to cool in the pan for 5 minutes. 

  After the 5 minutes of cooling in the pan, turn the cake out onto the wire rack and quickly pour the 7up over the hot cake.

  Allow the cake cool completely on the rack. 

Prepare the 7up Glaze (while the cake is baking or cooling)

• In a small mixing bowl, whisk together the powdered sugar, lemon and lime juices and the remaining zests.

  Add 7up to thin to your desired consistency. Whisk until smooth.
• The glaze is safe, covered, at room temperature for 2-3 days. You can also transfer the glaze to a storage bag and refrigerate for 1 week.

Glaze the 7up Cake

• Spoon the 7up glaze over the surface of the cake. Use as much, or as little, glaze as you prefer. 

  Decorate your cake with slices of lemon and lime or serve it as is.