Preheat oven to 350°F. Grease and flour three 9-inch round cake pans. Beat eggs in a large bowl with an electric mixer until light yellow, about 5 minutes. Gradually add the sugar and mix at medium speed until thoroughly blended.
In a separate bowl, combine baking powder, baking soda, butter, oil, cocoa powder, buttermilk, and vanilla extract. Mix until well combined. Add the flour and salt to the egg mixture and stir in until just blended.
Slowly add the chocolate chips and mix on low speed for about 2 minutes. Gradually pour in the boiling water and continue mixing until all ingredients are thoroughly combined. Divide batter evenly among the cake pans.
Bake for 30 minutes or until a toothpick inserted into the center of each cake comes out clean. Cool in the pans for 10 minutes, then turn onto wire racks to cool completely. Once cooled, frost as desired.