• Preheat the oven to 350°F/180°C. Grease two 8-inch cake pans and line the bottom of the pans with parchment paper.
• In a small bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
• In a bowl of a stand mixer fitted with a paddle attachment or in a medium bowl and electric mixer, beat the butter, oil, and granulated sugar on high speed for around 3-4 minutes until it's very light in color and creamy.
• Add in the vanilla and eggs, one at a time, and beat in after each addition.
• In a small bowl, stir together the milk and vinegar.
• Add half the dry ingredients to the butter mixture, stir them in, then add half the milk. Use a rubber spatula to stir it in well until well combined. Repeat with the rest of the dry ingredients and milk mixture.
• Divide the cake batter evenly amongst the cake pans and smooth down the tops of the batter with a small offset spatula.
• Bake the cakes for around 30 minutes until the tops spring back when touched and a skewer inserted into the middle of the cakes comes out clean.
• Remove the cakes from the oven and let them cool for 10 minutes in their pans, then turn them onto a wire cooling rack and allow them to cool completely.

Frosting

• In a small bowl combine the cream and toasted milk powder and stir to combine.
• In the bowl of a stand mixer fitted with a paddle attachment beat the butter until light, smooth and creamy. Add in the powdered sugar, salt, vanilla, and heavy cream mixture.
• Whip at low speed to combine the sugar, then beat at high speed for 5-8 minutes until it is thick and fluffy. The longer you beat it, the fluffier the frosting will be.
• Place one cake layer on a cake turntable or cake stand. Scoop on some frosting and use a small offset spatula to spread the frosting on top of the cake layer. Add on the second cake layer. Placing the top layer upside down will give a nice, smooth top to work with.
• Add a few scoops of frosting on top, spread it out with the spatula, and add a thin coat of frosting around the cake. Use a bench scraper to smooth it out, then chill the cake for around 20 minutes in the fridge until the frosting has firmed up.
• Add a thicker layer of frosting to the cake and use a bench scraper to smooth it out. Then, you can use a serrated bench scraper to make patterns on the side of the cake if you wish.