Step 1

In a small saucepan, whisk flour and milk together until well-combined.

Step 2

Heat, stirring constantly, until it thickens.

Step 3

Remove from heat, and let it cool to room temperature.*

Step 4

Stir in vanilla.

Step 5

While the mixture is cooling, cream the butter, sugar, cocoa powder, and salt together until light and fluffy on medium high, about 5 minutes.

Step 6

Add the completely cooled milk mixture.

Step 7

Beat it for about 5 minutes on high until it looks like whipped cream. It may look separated at first, so keep beating it until it comes together and looks like a whipped cream.

Step 8

If it looks separated after about 7 minutes of whipping, cover, and chill for about 30 minutes. Then, continue whipping for about 5 minutes, or until it looks like whipped cream.