Step 1

Preheat the oven to 350 degrees Fahrenheit. Grease and line a 9x13-inch baking pan with parchment paper and set aside.

Step 2

Make the Cake: In a medium bowl, whisk or sift the flour, baking powder, baking soda, and salt. Set aside.

Step 3

In a separate bowl, beat the butter and sugar with a hand or stand mixer at medium speed until light and fluffy, about 3-4 minutes.

Step 4

Reduce the speed to low and blend in the oil, eggs, and vanilla one by one until smooth.

Step 5

Alternate adding the flour mixture and buttermilk to the batter. Begin and end with the flour (three parts flour, two parts buttermilk) mixing just until combined.

Step 6

Pour the batter into the prepared pan and spread it evenly. Bake for 35-40 minutes or until a toothpick inserted into the center comes out clean. Let the cake cool completely in the pan on a wire rack.

Step 7

Make the Frosting: Beat the butter at medium speed until creamy. Gradually add powdered sugar, followed by the vanilla and salt, mixing until smooth. Add the buttermilk a little at a time and beat until light and fluffy.

Step 8

Spread the frosting evenly over the cooled cake. Decorate with sprinkles or other toppings if desired, then chill for 15-20 minutes to allow it to set. Enjoy!