• Preheat the oven to 350°F.
• Grease a pair of 8-inch or 9-inch cake pans then line the bottom with a parchment paper circle. Using 8-inch cake pans result in thicker layers and 9-inch in slightly thinner layers.

Make the Cake Batter

• In a medium bowl, sift together the flour, baking powder, baking soda and salt and set aside.
• In a large mixing bowl, beat the butter with an electric hand mixer until lighter in color - about 1 minute.
• Add the sugar and mix at medium high speed until light and fluffy, about 2 minutes, scraping the sides as needed.
• Reduce to a low speed and add the egg whites until they are all combined.
• Add the oil and vanilla, then blend again to combine.
• Alternate the flour mixture and buttermilk, starting and ending with the flour mixture. Combine at a low speed, then increase to medium for another minute.
• Divide the batter between the 2 prepared cake pans (about 23 ounces per cake pan if you want to weigh it with a digital kitchen scale).

Bake the Cakes

• Bake for 28 to 32 minutes until a toothpick inserted into the center comes out clean.
• Let the cakes cool in the pans for 10 minutes.
• Remove from the pans and cool completely on a wire rack.

Make the Frosting

• Put the ricotta cheese in the center of a piece of cheesecloth or a cheesecloth bag and squeeze it to remove as much moisture as possible.
• Place the strained ricotta cheese in the mixing bowl of a stand mixer and add the mascarpone cheese.
• Using the paddle attachment, blend on medium speed for 2 minutes until combined. Add the clear vanilla and orange zest and mix again on low speed for 1 minute.
• Add the powdered sugar and mix at low speed, about a cup at a time until mixed in, then increase the speed to mix completely.
• Pro tip: Fill a piping bag fitted with a Wilton 1M star tip with 12 Ounces of frosting for decoration.

Assemble the Cake

• Once completely cooled, slice each cake horizontally to make 4 even layers. This can be done with a cake wire cutter, or on a turntable with a serrated knife and very very steady hands. Note: This is a lighter, more fragile cake than traditional layer cakes and each cake must be completely cooled before cutting. You can put each half into the freezer for 10 to 15 minutes first.
• Place one cake layer on a serving plate or cake stand and top with some frosting and ¼ cup of the mini chocolate chips, gently pressing the chips into the frosting. Repeat with the next 2 layers.
• Add the last layer and frost the top and sides of the cake.

Decorate the Cake

• Garnish with additional swirls of frosting on top, another ¼ cup of mini chocolate chips in the center.
• Add mini chocolate chips around the bottom edge of the cake, if liked.
• Chill for about an hour before serving.