Cheese Potatoes

For cheese sauce, melt butter in a saucepot over medium heat. Stir in flour and cook, stirring constantly, until mixture turns a light almond color and smells nutty, about 4 minutes. Switching to a whisk, gradually pour in milk and whisk until smooth. Add nutmeg and mustard and let sauce come up to a simmer and thicken. Strain if necessary and return to pan. Reduce heat to low and stir in three