|Heat milk on stove or in a microwave until scalded. |
Melt butter in a 2-quart bowl in the microwave.
Stir in flour with a wire whisk until smooth. Cook in microwave about 1 minute.
Add hot milk and stir until smooth. Microwave about 3 minutes, stirring every minute, or until desired thickness, add sugar and salt and microwave 30 seconds more.