PLANTER'S PUNCH CAKE

Steps:

• Preheat the oven to 350 degrees F. Butter and flour a 9-by-13-inch metal baking pan. Line the bottom of the pan with parchment paper.
• Put the flour, baking powder, baking soda and salt in a large bowl and whisk to combine. Put the butter and both sugars in a second large bowl and beat with an electric mixer on medium-high speed until pale and fluffy, about 3 minutes. Add the eggs one at a time, beating well after each addition; beat until smooth, then add the sour cream. Add the flour mixture in 3 additions, alternating with the buttermilk, beginning and ending with the flour. Scrape down the sides and bottom of the bowl with a rubber spatula to ensure the batter is well mixed. Add the grenadine, lemon zest, lime zest and orange zest, and stir until just combined.
• Pour the batter into the prepared pan and smooth the top. Bake until the cake is light golden on top and a toothpick inserted into the middle comes out clean, 25 to 30 minutes. Transfer the cake to a cooling rack and let cool for 10 minutes. Invert the cake onto the rack, unmold from the pan and remove the parchment paper. Turn the cake right-side up on the rack and let cool completely before serving.