Preheat oven to 350ºF and line a 12-cup standard muffin pan with cupcake liners; set aside.
In a mixing bowl, add flour, baking powder and salt; whisk until well blended.
In the bowl of a stand mixer, add butter and sugar. With the paddle attachment, process on medium-high speed until the mixture is creamy, scraping the sides of the bowl if needed.
Add grapeseed oil and process for 1 minute.
Add one egg at a time, mixing well between each addition. Add vanilla extract and process to combine, about 30 seconds.
Reduce the speed to medium-low and add 1/3 of the dry ingredients as well as 1/3 of buttermilk, mixing very well between each addition; scrape the bottom of the bowl and the sides as needed.
Divide the batter evenly into the prepared muffin cups, filling them up to 2/3rds full.
Transfer to the preheated oven and bake for 20 to 22 minutes or until a cake tester inserted in the center comes out clean with a few little crumbs.
Remove from the heat and let them cool 5 minutes before transferring them to a wire rack to cool completely before frosting.