Preheat oven to 350 degrees Fahrenheit. Grease and line with parchment paper 3 8-inch round cake pans.
Sift flour, baking powder, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using a hand mixer, beat together the butter, oil, and Domino® Golden Sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition. Mix in the vanilla extract and half of the buttermilk.
Add half of the dry ingredients and mix on low speed until just combined. Mix in the remaining buttermilk. Finally, add the remaining dry ingredients and mix until there are no more dry spots and the batter is smooth.
Divide the batter evenly into the prepared cake pans and bake for 35-40 minutes, or until a wooden skewer inserted into the center comes out clean.
While the cake layers are cooling, prepare the salted caramel and buttercream.