01 - Preheat oven to 350°F. Grease and flour two 9-inch round cake pans and line bottoms with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, salt, and cocoa powder until well combined.
03 - In a separate bowl, whisk buttermilk, oil, eggs, vanilla, vinegar, and green food coloring until smooth and uniform.
04 - Add wet ingredients to dry ingredients. Mix until just combined—do not overmix to maintain tender texture.
05 - Divide batter evenly between prepared pans, smoothing tops with a spatula.
06 - Bake for 28–32 minutes or until a toothpick inserted in the center comes out clean.
07 - Cool cakes in pans for 10 minutes, then turn out onto wire racks to cool completely before frosting.
08 - Beat cream cheese and butter until creamy. Add powdered sugar, vanilla, and salt; beat until fluffy and spreadable.
09 - Place one cake layer on a serving plate. Spread with frosting. Top with second layer and frost top and sides evenly.
10 - Decorate with green sprinkles or edible glitter if desired. Serve immediately or refrigerate until ready to serve.