Preheat oven to 180°c. Grease three 9-inch cake pans and line the bottoms with parchment paper.
Whisk together the flour, baking powder, bicarbonate of soda, and salt.
Cream together the butter and sugar in a mixer at medium-high speed for 3 – 5 minutes or until very light and fluffy. Turn mixer to low and add the oil. Scrape down the sides of the bowl and give it another mix.
Mix in the eggs, one at a time, blending well, and scraping down the sides of the bowl after each addition. Mix in the vanilla and soured cream.
With mixer on low, add in 1/3 of the flour mixture, followed by half the buttermilk, another 1/3 of the flour, the rest of the buttermilk, and the final amount of flour. Scrape the sides of bottom of the bowl to make sure everything is fully combined. Add the sprinkles and stir. Divide the batter among the prepared cake pans.
Bake for 30 – 35 minutes, or until a toothpick inserted in the centre comes out clean. Let cool in the pans for 30 minutes. Run a knife around the edges of the pans, place on a cooling rack, peel off the parchment, and allow to cool completely.
