Ingredients  Cola Syrup 3   cups   cola soft drink .50   cup   granulated sugar 2   tablespoons   fresh lemon juice Cake Baking spray with flour 1   cup   unsalted butter (8 ounces), softened ¾   cup   packed light brown sugar .50   cup   granulated sugar 2.50   cups   all-purpose flour (about 10 5/8 ounces) ¼   cup   unsweetened cocoa 1   tablespoon   instant espresso powder 1   teaspoon   kosher salt 1   teaspoon   baking soda 1   teaspoon   ground cinnamon .50   teaspoon   baking powder .50   teaspoon   ground nutmeg ⅛   teaspoon   ground cloves 2   large eggs plus 2 large egg yolks, at room temperature ⅔   cup   buttermilk .50   cup   sour cream 1.50   teaspoon   vanilla extract 1   teaspoon   grated orange zest 1   teaspoon   grated lemon zest Glaze ¾   cup   powdered sugar (about 3 ounces) 2   tablespoons   unsalted butter, melted 1   tablespoon   unsweetened cocoa 1   teaspoon   whole milk Additional Ingredients Sweetened whipped cream and amarena cherries (optional) Directions Make the cola syrup: Bring cola and sugar to a boil in a medium saucepan over medium-high. Boil, uncovered, stirring occasionally, until reduced to 1 cup, 30 to 40 minutes. Remove from heat. Stir in lemon juice. Reserve 1/4 cup cola syrup in a liquid measuring cup for glaze. Make the cake: Preheat oven to 350°F. Coat a 12-cup Bundt pan with baking spray. Stir butter, brown sugar, and granulated sugar into remaining 3/4 cup cola syrup in saucepan. Cook over medium-low, stirring often, until butter is melted and sugars are dissolved, about 3 minutes. Remove from heat. Let cool 5 minutes. Whisk together flour, cocoa, espresso powder, salt, baking soda, cinnamon, baking powder, nutmeg, and cloves in a large bowl. Whisk together eggs and egg yolks, buttermilk, sour cream, vanilla, and zests in a medium bowl; gradually whisk in slightly cooled syrup mixture until well combined. Make a well in center of flour mixture; add egg mixture, stirring until well combined. Spoon batter into prepared Bundt pan. Bake in preheated oven until a wooden pick inserted in center of cake comes out clean, 40 to 45 minutes. Let cake cool in pan on a wire rack 15 minutes. Invert cake onto wire rack, and let cool completely, about 1 hour and 30 minutes. Make the glaze: Whisk together powdered sugar, melted butter, cocoa, and reserved 1/4 cup cola syrup in a medium bowl until smooth. Whisk in milk until creamy, pourable, and smooth. Place cake on a plate. Pour glaze over cake. Let stand at room temperature 10 minutes. Serve with whipped cream and cherries, if desired.