In a heavy-bottomed saucepan, pour in the whole milk and heat it over medium heat until it reaches 195°F. Stir continuously to prevent the milk from burning on the bottom.

While your milk is heating, whisk together the all-purpose flour, granulated sugar, and Morton kosher salt in a small bowl until thoroughly combined. Set aside.

Melt the salted butter in a separate small saucepan over medium heat, ensuring it doesn't brown. Once fully melted, remove from heat.

When your milk has reached 195°F, slowly stir the flour mixture into the melted butter to create a thick paste, then gradually add it into the hot milk, stirring constantly until it begins to boil.

Once boiling, reduce the heat to low and cook the Rømmegrøt for an additional 5 minutes, stirring often until thickened to a pudding-like consistency.

Carefully spoon the Rømmegrøt into serving bowls, drizzle with warm melted butter, and sprinkle with cinnamon-sugar before serving.