3/4C (6 oz) (170 gr)unsalted butterat room temperature
1/4C (2 fl oz) (60 ml)vegetable oilsoft flavored
1 1/2C (10.5 oz) (300 gr)white sugar
3eggs
2eggs yolks
1tbsp (0.50 fl oz) (15 ml)vanilla extract
2 1/4C (9.5 oz) (270 gr)all purpouse flour
1/4C (1.30 oz) (37 gr)corn starch
1/2tsp (3.5 gr)salt
2tsp (14 gr)baking powder
1/2tsp (3.5 gr)baking soda
1C (8 fl oz) (240 ml)buttermilk
For the frosting:
1C (8 oz) (225 gr)unsalted butterat room temperature
1 1/3C (5.8 oz) (165 gr)confectioners sugar
2/3C (2 oz) (56 gr)cocoa powdersugar free
1tsp (5 ml)vanilla extract
1pinchsalt
1/3C (2.70 fl oz) (80 ml)whipping cream
2.5oz (75 gr)semi sweet chocolate
Instructions
For the cake:
Preheat the oven to 375ºF (180ºC). Grease two round cake pans of about 9 inches (23 cm) diameter.
In a medium sized bowl, sift the flour along with the corn starch, salt, baking powder and baking soda.
In a big bowl, using an electric mixer, cream together the butter and sugar for 3 minutes until the mixture becomes fluffy and lightens in color.
Add the oil and butter and mix until fully integrated. Mix in the eggs and egg yolks one by one, beating after each addition.
Add in the flour mixture in three separate additions alternating with the buttermilk, beating after each addition. Mix well until smooth.
Pour the mixture in the two cake pans and bake for about 20 minutes aprox until a wooden stick comes out clean when inserted.
Once ready, let the cakes rest for about 10 minutes. Turn them out and place them on a cooling rack to completely cool down.
For the frosting:
Cut the chocolate un small pieces and place them in a heat resistant bowl. In a small pot to medium heat or in the microwave, heat the whipping cream to bring it to a boil.
Once boiling, pour it over the chocolate pieces, let it sit for 3 minutes and then mix until fully integrated to form a ganache.
In a big bowl, using an electric mixer, cream together the butter and confectioners sugar, salt and vanilla extract for 3 minutes until you get a lighter in color and fluffy mixture.
Add in the cocoa powder (sifted) and continue to beat for 2 more minutes until you get a smooth mixture.
Once cool, add the ganache and beat for 2 more minutes until the mixture is soft and creamy. Refrigerate the frosting for 15 minutes.
To assemble:
Place one of the cakes on a big plate or cake stand (which is where the cake will be presented). With a spoon spread a third of the frosting over the cake´s top.
Place the other cake on top and then slowly spread the rest of the frosting all over the cake. Spread the frosting on the sides of the cake with a spoon, making circles to form "waves" and decorate.
Refrigerate the cake for 30 minutes before cutting.