01 -  Preheat oven to 350°F. Grease and line a 9x13-inch sheet pan with parchment paper. 
 02 -  Whisk together the flour, granulated sugar, baking powder, baking soda, and salt in a large mixing bowl. 
 03 -  In a separate bowl, whisk cream soda or root beer, melted unsalted butter, eggs, and vanilla extract until well combined. 
 04 -  Gently fold the wet ingredients into the dry mixture, stirring until just combined. Avoid overmixing. 
 05 -  Pour batter into the prepared pan and smooth the top. Bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out clean. 
 06 -  Place the pan on a wire rack and allow the cake to cool completely before frosting. 
 07 -  In a mixing bowl, beat softened butter until creamy. Gradually add powdered sugar, then blend in cream soda or root beer, heavy cream, vanilla extract, and a pinch of salt. Beat until light and fluffy. 
 08 -  Spread frosting evenly over the cooled cake. 
 09 -  Decorate with maraschino cherries, rainbow sprinkles, and whipped cream as desired. 
 10 -  Slice sheet cake and serve immediately.