Preheat oven to 350º F (180º C). Line 3 8-in (20 cm) round cake pans with parchment paper. Lightly grease with baking spray with flour.
Sift the flour and baking powder into a large bowl. Add salt and mix to combine.
Combine milk and vinegar in a small bowl. Set aside.
Using an electric hand mixer or a stand mixer, beat butter until creamy on medium-high speed, about 3 – 4 minutes. Add the sugar and beat on high speed for 4 minutes until creamed and pale, scraping down the sides and up the bottom of the bowl with a rubber spatula as needed. Then add vanilla; continue beating to combine, about 1 minute.
Turn the mixer to low and add the flour mixture in three batches, alternating with milk mixture, beginning and ending with the flour mixture; beat until just combined, about 30 – 45 seconds. Do not overmix.
Evenly divide the batter between prepared pan (2 1/2 cups of batter in each pan approximately).
Bake for 20 – 25 minutes, or until a toothpick inserted in the center comes out clean. Let the cakes cool in their pans on wire racks for 10 minutes before removing them from the pans. Allow the cakes to cool completely, right-side up, on a wire rack before removing the parchment paper.