Croque Monsieurs (Baked Ham and Cheese Sandwiches)

I remember the very first time I had one of these rich and cheesy sandwiches.  I could barely see above the counter, but I remember my godmother whipping whisking the roux on the stove.  Then piling the French bread she'd just bought that morning from the local baker with an impossible amount of cheese.   She was French and lived part of the time in California and other part in an apartment in Monaco.  Whenever she visited, this is what she would make us for lunch.   And there was always a little salad of greens coated in a tangy vinaigrette.