01 -
Turn your oven to 350°F/180°C. Prep three 6-inch pans with parchment and butter them up.
02 -
In a big jug, mix together the milk, vanilla, whole egg, and egg whites. Set this aside for now.
03 -
Using a mixer with a paddle, stir all the dry stuff on low for a minute. Toss in cold butter and mix until crumbly.
04 -
Pour the liquids into the dry mix in two rounds. Scrape the sides and base of the bowl before and after each go. Blend it till smooth and airy.
05 -
Split the batter into the pans as evenly as you can. Bake for 25–35 minutes. A few crumbs on a skewer means they're done.
06 -
Leave the cakes to cool in the pans for 20 minutes before lifting them out.
07 -
Level the layers. Spread frosting between each one. Apply a thin coat, chill 30 mins, then finish with a final coat and sprinkles.