Croque Monsieur from Petit Trois

Mornay Sauce
1. Over medium heat melt butter, add onion, a pinch of salt and a dash of frehly ground black pepper.
2. Cook for about 10 minutes over a low-med heat until onion is soft, but no
coloration.
3. Remove from heat, slowly adding in flour and whisking until combined with butter/onions.
4. Over low heat cook for a couple of minutes until flour is completely absorbed, stirring constantly so no coloration.
5. Slowly whisk in milk and add bay leaf.
7. Bring mixture to a boil, then reduce heat and simmer for 20-30 minutes stirring occasionally until thick and smooth.
8. Remove from heat and strain through fine mesh sieve.

Assembling the sandwich
1. Butter the bread slices on one side.
2. Place half of the slices butter side down on a sheet tray.
3. Cover each slice with Gruyere cheese slices with a little
hanging over the edges.
4. Top with 3-4 slices of ham.
5. Cover each with the other slice of bread, buttered side up.
6. Cover each grilled sandwich with Mornay sauce.
7. Heat under broiler until sauce is boiling about 2 minutes.
8. Top with chives.