Preheat Oven and Prepare Pans: Preheat the oven to 350°F (175°C). Grease and flour three 9-inch round cake pans, tapping out any excess flour.
Sift Dry Ingredients: Sift the flour, baking powder, and baking soda into a large bowl. Set aside.
Cream Butter and Sugar: In an electric mixer fitted with the paddle attachment, beat the butter, oil, salt, and sugar on high speed until light and fluffy, about 5 minutes.
Add Eggs and Vanilla: With the mixer on low, add the eggs one at a time, scraping down the bowl after each addition. Mix in the pure vanilla extract, clear vanilla flavor, and vanilla bean seeds until well combined.
Combine Dry and Wet Ingredients: Alternately add the dry ingredients and evaporated milk to the batter in three parts, beginning and ending with the dry ingredients. Mix until just combined, taking care not to overmix.
Bake: Divide the batter evenly among the prepared pans. Bake for 25 to 30 minutes or until a toothpick inserted in the center comes out clean.
Cool: Let the cakes cool in the pans on racks for 15 minutes, then invert them onto the racks, remove the parchment paper, and cool completely.