Preheat your oven to 175°C (350°F) and grease your cake pans, then line them with parchment paper

In a medium bowl, whisk together flour, baking powder, and salt until evenly combined

In a large mixing bowl, beat softened butter and sugar together until pale and fluffy, about 3 to 4 minutes

Add eggs one at a time, mixing well after each addition to ensure a smooth batter

Mix in vanilla extract to enhance the flavor

Pour in the vegetable oil and continue mixing until fully incorporated

Gradually add the dry ingredients in three parts, alternating with milk

Start and end with the dry ingredients to maintain a smooth batter

Mix just until combined, avoiding overmixing which can make the cake dense

Divide the batter evenly between prepared cake pans

Tap the pans gently on the counter to remove air bubbles

Bake for 28 to 32 minutes or until a toothpick inserted in the center comes out clean

Allow cakes to cool in the pans for 10 minutes before transferring to a wire rack

Let the cakes cool completely before frosting

For the buttercream, beat butter until creamy and smooth

Gradually add powdered sugar while mixing on low speed

Add vanilla extract, salt, and milk, then beat until light and fluffy

Adjust consistency by adding more milk if needed

Place one cake layer on a serving plate and spread an even layer of frosting

Add the second layer and apply a thin crumb coat

Chill the cake for 15 to 20 minutes to set the base layer

Apply the final coat of frosting evenly using an offset spatula

Decorate with sprinkles or fresh berries if desired

Slice and serve once frosting is set