Preheat your oven to 350°F. Grease and flour two 9-inch cake pans.
In a large bowl, whisk together the flour, baking powder, and salt.
Combine milk and apple cider vinegar in a separate bowl and let it sit for a minute to create a homemade buttermilk.
In another bowl, cream together the softened butter and sugar until light and fluffy.
Gradually mix the dry ingredients into the butter mixture, alternating with the milk mixture, starting and ending with the dry ingredients.
Stir in the vanilla extract until just combined.
Divide the batter evenly between the prepared pans and smooth the tops.
Bake for 25 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then turn out onto a wire rack to cool completely.
Spread your favorite frosting on the top of one cake layer. Place the second cake layer on top and add more buttercream on the top and around the sides of the cake. Garnish with sprinkles.