Classic Ermine Frosting

Combine milk and flour in a saucepan over medium-high heat, stirring vigorously throughout the process until the mixture thickens to a pudding-like consistency. Bring the mixture to a rolling boil, then carefully transfer it to a heat-resistant vessel. Cover the top of the container with a sheet of parchment paper, ensuring it makes direct contact to prevent a skin from forming. Chill in the refrigerator for an extended period, ideally 8 hours or overnight.

Melt sugar and butter together in a mixing device using a high-speed mixer, incorporating salt into the process until it is fully dissolved. Continue blending until sugar granules have vanished completely.

Retrieve the chilled milk mixture from the refrigerator and gently stir it with a spoon to verify there are no lumps. Gradually pour the milk mixture into the sugar and butter mixture, blending on a low speed until it is fully incorporated. Stop the mixer momentarily to scrape down the bowl, ensuring all ingredients are well combined. Increase the speed to medium and continue beating until the frosting achieves a light and airy texture, taking around 5-10 minutes. Finally, incorporate vanilla extract into the mixture.