In a heavy-bottomed saucepan, gently heat 4 cups of whole milk over medium heat until it reaches 195°F, stirring almost continuously.

Whisk together 1 cup of all-purpose flour, ½ cup of granulated sugar, and 1 teaspoon of Morton kosher salt in a mixing bowl.

In a small saucepan, melt ½ cup of salted butter over low heat and stir in the flour mixture to create a paste.

Gradually whisk the butter-flour paste into the warm milk and stir constantly until it comes to a gentle boil.

Lower the heat and let it simmer for about 5 minutes, stirring continuously until it thickens to a pudding-like consistency.

Serve the warm Rømmegrøt in individual bowls, drizzle with melted butter, and sprinkle with cinnamon-sugar.