Preheat oven to 325˚F. Spray an 8-inch round cake pan with 2-inch sides. (If your 8-inch cake pan does not have 2-inch sides, use a 9-inch pan.) Line the pan with a round of parchment paper.
Add vanilla and powdered sugar and soft butter and whisk well to combine. Continue whisking until the icing is smooth and spreadable. If it’s too thin add a bit more powdered sugar, if too thick and a teaspoon of half and half at a time until nice and spreadable.
Put a big dollop of frosting in the center of the cooled cake. Using an offset icing spatula, spread it to the edges and down the sides, adding more frosting to the top as you work your way around the cake. When the cake is completely iced, you can go back and add some swirls, if desired. Sprinkle with flaky sea salt and enjoy!
See Café Tips above in post for more details instructions and tips.