01 -  Preheat oven to 350°F. Grease and line two 9-inch round cake pans with parchment paper. 
 02 -  In a medium bowl, whisk together flour, baking powder, baking soda, and salt. 
 03 -  In a large bowl, cream unsalted butter and granulated sugar until light and fluffy, about 3 minutes. Beat in eggs one at a time, then mix in vanilla extract. 
 04 -  On low speed, add the flour mixture in three additions, alternating with lemon-lime soda. Begin and end with the flour mixture, mixing until just combined. 
 05 -  Divide the batter evenly between prepared pans. Bake for 25 to 30 minutes or until a toothpick inserted in the center comes out clean. 
 06 -  While the cakes bake, combine 1/2 cup lemon-lime soda and 2 tablespoons granulated sugar in a small saucepan. Heat over medium until sugar dissolves. Remove from heat and set aside. 
 07 -  Let cakes cool in the pans for 10 minutes before turning onto wire racks. While still warm, brush each layer with soda syrup using a pastry brush. Let cool completely. 
 08 -  Simmer 1/4 cup lemon-lime soda in a small saucepan over medium heat until reduced to 2 tablespoons. Allow to cool completely. 
 09 -  Beat softened butter and cream cheese together until smooth. Gradually blend in powdered sugar. Add cooled soda reduction, vanilla extract, and salt. Beat frosting until fluffy. 
 10 -  Place one cake layer on a serving plate and spread with one-third of the frosting. Top with second cake layer and frost top and sides with remaining frosting. 
 11 -  Garnish with maraschino cherries and sprinkles. Chill cake for 20 minutes before slicing to achieve clean cuts.