Preheat oven to 350 degrees F.
Grease three 9-inch round non-stick cake pans with butter. Line the bottom of each pan with a round piece of parchment paper. Set aside.
Whisk the dry ingredients: In a bowl, whisk the sifted flour, baking powder, baking soda, and salt. Set aside.
Combine the wet ingredients: In a large bowl, whisk the vegetable oil, sugar, eggs, buttermilk, vanilla extract, lemon juice, and lemon zest until evenly combined.
Using a rubber spatula, fold in the wet ingredients into the dry ingredients until combined and no pockets of flour remain. It should be evenly combined but not over-mixed.
In a another bowl, toss the raspberries with 1 tablespoon of all-purpose flour. Fold it into the batter until just combined. Be careful not to break the raspberries, they are very delicate.
Divide the batter evenly across the 3 prepared cake pans. Bake for 21 to 23 minutes, or until a toothpick inserted in the middle comes out clean. Tip: Opening and closing the oven too much can cause the center of the cakes to sink. Just let it bake until time is up.
Let them cool in the pan completely for a few hours (usually, about 3 to 4 hours). Optional make-ahead: After they have cooled completely, remove them from the pan and wrap each one with plastic wrap. Refrigerate for 1 day so you can assemble it the next day.