Step 1: Preheat your oven to 350°F. Grease and flour two 9-inch cake pans.
Step 2: In a large mixing bowl, combine the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
Step 3: Add in the buttermilk, vegetable oil, eggs, and vanilla extract. Mix until well combined.
Step 4: Stir in the boiling water, orange zest, and orange extract. The batter will be thin, but don't worry, that's normal!
Step 5: Divide the batter evenly between the two prepared cake pans. Bake for 30-35 minutes or until a toothpick inserted into the center of the cake comes out clean.
Step 6: Remove the cakes from the oven and allow them to cool completely in the pans.
Step 7: While the cakes are cooling, prepare the frosting. In a large mixing bowl, beat the butter and vegetable shortening together until light and fluffy.
Step 8: Add in the orange juice, orange extract, and confectioner's sugar. Beat until well combined and the frosting is smooth.
Step 9: Add in the orange food coloring until you reach your desired shade.
Step 10: Once the cakes have cooled, remove them from the pans and level the tops with a serrated knife.
Step 11: Place one cake layer on a cake plate or stand. Spread a layer of frosting on top.
Step 12: Place the second cake layer on top of the frosting. Spread a thin layer of frosting all over the cake. This is called the crumb coat and will help the final layer of frosting go on smoother.