In a large saucepan set to medium high heat, warm the milk to 195° F. Stir almost continuously so the milk does not burn, scraping the bottom of the saucepan with a heat resistant rubber spatula.

While the milk is warming, whisk together the flour, sugar and salt in a small bowl, then set aside.

In a small sauce pan melt the butter over medium heat. Turn off the heat.

When the milk has reached 195° F in temperature, stir in the flour mixture into the melted butter to form a thick paste.

Add the flour butter mixture to the heated milk. Stirring constantly until the milk starts to boil. Turn the heat down to low and let it cook for 5 minutes more, stirring often. Remove the saucepan from the heat.

Spoon the pudding into individual bowls and serve with warm melted butter and a sprinkle of cinnamon sugar.