This recipe came from an old, old cookbook belonging to my grandmother. I have made this with 2 layers, 3 layers or 2 layers split to make 4 layers. It is an extremely moist cake and a beautiful presentation. I have also used orange extract in the cake instead of vanilla extract. It is also good using a cream cheese frosting instead of the whipped cream frosting.
Preheat oven to 350. Lightly butter three 9-in. cake pans, line with parchment paper, then lightly butter and flour the paper.
Sift the flour, baking powder, and salt into a large bowl. Sift a second time into another bowl. In the bowl of a mixer, beat the butter on med. speed until light in color. Add 2-2/3 c. sugar in a steady stream with the mixer running. Beat until light and fluffy. Add the eggs and yolks, one at the time, beating well after each addition, scraping down sides of bowl. After eggs are added continue to beat for 2 more minutes on med. speed. Turn mixer to low speed and add the oil. Beat for 1 minute. In a small mixing bowl combine orange zest, vanilla and buttermilk. Fold in half the dry ingredients to the egg and sugar mixture. Scrape down sides of bowl and add half the buttermilk mixture. Fold in remaining dry ingredients, then remaining buttermilk mixture. Pour batter into prepared pans and bake for 30-35 minutes. Cool on racks approx. 20 minutes.
For orange syrup: stir together orange juice and 1/4 c. sugar until sugar is dissolved. While cakes are in cakepans use a toothpick and poke holes in the cake layers. Spoon syrup over each layer. Let the layers cool completely in the pans.
Filling: Heat marmalade over med. heat until melted. Let cool for 5 minutes.
Frosting: In chilled mixing bowl whip the heavy cream with 8 T. sugar until stiff peaks form. Add vanilla extract.
Assembly: Place one cake layer on cake plate. Peel off parchment paper. Spread 1/3 marmalade on top. Place 2nd cake layer on top, peel of parchment, spoon 1/3 marmalade on top. Place third layer on top, remove parchment, spoon remaining marmalade onto center of cake leaving 1-1/4 inche border around the edges. Frost the sides and top border with frosting leaving marmalade exposed. Chill at least 2 hours.