Let's start with making the cake. Place the rack in the lower third of your oven, preheating it to 350 degrees F. Butter four nine-inch round pans, lining it with parchment paper.

Mix both the sugar and vegetable oil in a bowl, beating it with a mixer on medium-high speed until it's thick and creamy. This will take about three minutes. Beat in the eggs after, one at a time. Add the vanilla as well then beat it all on high speed for two minutes or once the batter is fluffy and light.

Sift the dry ingredients (salt, flour, and baking soda) in a separate bowl. Mix it on low speed. In the bowl of the sugar mixture, beat in the flour mixture and buttermilk alternatively (in three additions), starting and ending with the flour mixture.

Divide the batter into four bowls, tinting each one with the four different colors. Pour it into the four different pans after.

Bake the cake two pans at a time for 15 minutes, or if you prick a toothpick in the center and once taken out, it becomes clean. Let the pans cool for 15 minutes after and prepare the frosting while doing so.

Make the frosting by beating the butter and salt in a bowl with the mixer on medium speed. Beat it for about two minutes or until the mixture is fluffy and smooth. Add in the confectioners' sugar gradually until it is smooth again, then add the vanilla. Place the speed on medium high, beating it until the mixture is thick, which would take about two minutes. Add the milk a little at a time and continue to beat it until the frosting is now spreadable.

Assemble the cake by spreading about a cup and a half of frosting between each cake layer, covering the outside of the cake using the frosting leftover. Pipe the remaining frosting on the ends of the cake and top it with a small strawberry slice.

Serve and enjoy!