- Preheat oven to 350°F. Spray 2 – 9-inch round cake pans with Baker’s Joy® No Stick Spray; set aside.
- In a medium bowl, whisk together the flour, baking powder and salt; set aside.
- In a mixing bowl, cream together the butter, shortening, sugar, vanilla extract, and orange peel until creamy; about 3-4 minutes. Scrape the sides of the bowl a time or two during this step.
- Alternate adding the flour mixture and the buttermilk, beginning, and ending with the flour. Mix just until incorporated.
- In a clean mixing bowl with clean beaters, beat the egg whites on med-high speed until stiff peaks form. Fold into the cake batter.
- Divide evenly among the two pans.
- Bake for 22-27 minutes or until a toothpick inserted in the center comes out clean.
- Allow to cool on a wire rack for 10-15 minutes then remove from the pans and cool completely on wire racks.
- In a double boiler, whisk together the egg yolks, sugar, zest, orange juice and lemon/lime juice.
- Turn heat on medium and bring water in double boiler to a boil while whisking constantly.
- Keep water at a steady boil and continue to whisk constantly for 10-12 minutes or until thickened.
- Remove from heat and stir in a few pieces of butter at a time, adding more as the butter melts.
- Pour into a container and cover the top of the curd with plastic wrap to prevent a skin from forming.
- Allow to cool for 20 minutes then place in the refrigerator for 3-5 hours or overnight. Can be made several days in advance.
- In a mixing bowl, cream the butter and orange zest until smooth.
- Scrape the sides of the bowl and add the buttermilk. Mix for 1-2 minutes.
- Gradually add the powdered sugar, mixing well after each addition, until the desired consistency is achieved.
- Slice each cake into two even layers.
- Place one piece on a platter or plate, cut side up.
- Pipe a border around the cake with the frosting then spread 2 Tbsp. of the orange curd in the center of the icing.
- Top with the other half of that cake, cut side down.
- Repeat piping a border and adding curd on the remaining cake layers except the very top.
- Frost entire cake with a thin layer of frosting. Refrigerate cake for 1 hour.
- Remove cake from the refrigerator and frost the whole cake with remaining frosting.
- Pipe a border around the top of the cake and fill the center with the remaining orange curd.
Garnish ideas: sugared cranberries, candied orange peel, chopped toasted walnuts, white chocolate shavings