Really, Really Good (And Easy!) Buttercream Frosting - cooking recipe

Ingredients

1 cup salted butter, softened (2 sticks)
4 cups powdered sugar
1 teaspoon vanilla
2 tablespoons milk (any type except fat-free)
1 -2 tablespoon corn syrup (I used light)
1/3 cup unsweetened cocoa powder (for chocolate frosting) (optional)

Preparation

Put butter, milk, and vanilla in the bowl of a stand mixer (if you don't have a stand mixer, a hand mixer will do).
Mix on low speed until it just starts to come together, about a minute.
Scrape the sides of the bowl with a spatula. Increase to medium low speed and beat for about another minute.
Increase mixer speed to medium high and beat for about another or minute or so.
Add powdered sugar (and cocoa, if using). Beat on low speed until sugar is just barely incorporated. Scrape down the sides of the bowl, and increase speed slowly to medium. Beat for about a minute.
Check your consistency. This is very important because if your frosting is too thick, it will not spread well.
If your spatula does not glide through the frosting, add about a tablespoon of corn syrup and beat on medium for about 30 seconds.
When the frosting is just holding its shape, it is too thick (if you are wanting to pipe some decorations on your cake/cupcakes, now would be the time to set a little of this aside in a separate bowl).
Add another tablespoon of corn syrup and beat on medium for 30 seconds.
Repeat until the frosting seems to be of a good spreadable consistency (you don't want it too runny, or it will slide off the cake/cupcakes).
Once you get your frosting to a good, spreadable consistency, increase mixer speed to medium high and beat for one minute. This will get your frosting nice and fluffy.