How to Make It
Preheat oven to 350°F. Coat 2 (9-inch) round baking pans with cooking spray; dust with flour. Microwave chocolate chips in a microwavable bowl on MEDIUM (50%) until melted and smooth, about 2 minutes, stopping to stir every 30 seconds.
Beat granulated sugar, brown sugar, and butter with a stand mixer fitted with a paddle attachment on medium speed until well blended, about 4 minutes. Add eggs, 1 at a time, beating until just blended after each addition. Add melted chocolate, beating until just blended.
Sift together flour, baking soda, and salt in a bowl; gradually add to butter mixture alternately with sour cream, beginning and ending with flour mixture, beating on low speed until just blended after each addition.
Place cola in a microwavable cup; microwave on HIGH until hot, about 45 seconds. Gradually add cola to flour-butter mixture in a slow, steady stream, beating on low speed until just blended. Beat in vanilla. Pour batter evenly into prepared pans.
Bake in preheated oven until a wooden pick inserted in center of cakes comes out clean, 33 to 36 minutes. Cool in pans on wire racks 10 minutes. Remove cakes from pans. Transfer to wire racks, and cool completely, about 1 hour.
Spread Fudgy Cola Frosting between cake layers and on top and sides of cake. Garnish with sugar pearls.