Mornay sauce is a classic French white sauce. The compound made from adding grated hard or semi-hard cheese — typically, Parmesan, Swiss, or a 50-50 ratio of each — to the Mother Sauce known as béchamel.
The cheese sauce is often served with eggs, vegetables, chicken, and seafood and is a key component in the Kentucky Hot Brown.
Like most of you, I relish Thanksgiving leftovers. Stuffing, mashed potatoes, and turkey legs all possess a greater depth of flavor the next day. But white meat turkey always seems to taste worse the following morning. In my mind, consuming leftover turkey breast is up there with finishing day-old fish. To help matters, I decided to try a regional dish I've always wanted to make: the legendary Kentucky Hot Brown. 
This warm sandwich, created at the Brown Hotel in 1926, is an open-faced wonder of roasted turkey, bacon, and tomatoes on fat toast, drizzled with luscious Mornay sauce. Nearly a century later, there are many variations, but I returned to the original, a move I don't regret. I love how the creamy, nutty Pecorino cheese sauce offsets the lean tone of turkey breast. For a Thanksgiving leftover idea you'll be making for years to come, keep reading.
I've always wanted to be at Churchill Downs during the Kentucky Derby, and this year is no exception — especially since the Top Chef crew will be there, cooking up a storm. But if you're like me and will only be able to watch the races from the comfort of your home this weekend, get into the spirit by making a Louisville, KY, classic: the hot brown. 
In case you're not familiar with it, the hot brown is a creamy, rich, hot sandwich that's made of sliced turkey, bacon, toast points, and a cheesy Mornay sauce. Many aspects of the hot brown are up for debate, from the original creator of the sandwich and the year it was conceptualized to what type of cheese ought to go on the sandwich. But what's indisputable about this sandwich is that it's insanely indulgent, and a quintessential part of Kentucky cuisine.
For a version that's easy from start to finish, employ the use of sliced, roasted turkey. Or, impress your friends by going all out with an elaborate recipe that calls for making the turkey from scratch. See both versions of the sandwich when you read more
