Directions:
In a shallow pan, pour in the milk and flour. Cook on medium heat while whisking until thickened.
Whisk in white sugar and continue cooking until you see the first bubble pop, then continue to cook for 1 minute longer.
Pour the hot cooked flour mixture into a container and allow to cool.
Once the flour mixture has cooled, whip the softened butter with the whisk attachment until it is lighter in color and texture.
Add the flour paste to the whipped butter, and using the whisk attachment, whisk on low speed until all the paste has been added.
Whisk on high speed until it comes together and thickens slightly as the butter takes in the flour paste.
Switch to a paddle attachment to smooth it out. Flavor it with vanilla and salt, and add a tiny speck of purple food coloring if desired.
Store in the fridge and bring back to room temperature before using.