My youngest returned to university for the winter semester last weekend. This was the sandwich she requested for her Bon Voyage. Croque Monsieur . Easy. This makes two sandwiches.
Make two grilled Gruyere and ham sandwiches. While those are browning, make a white sauce.
1 Tbsp. butter
1 Tbsp. flour
1/2 cup milk
Pinch of salt and of nutmeg
Melt the butter in a saucepan. Add the flour and stir for a minute. Slowly whisk the milk into the roux. Add seasoning.
Pour the sauce over the top of the sandwiches. Add grated Gruyere to the top. Broil until bubbly (1-2 minutes)