Question: Mornay sauce includes what type of hard yellow cheese?

Context paragraphs:
Chicken Divan: Chicken Divan is a chicken casserole usually served with broccoli, almonds, and Mornay sauce.  It was named after the place of its invention, the Divan Parisienne Restaurant in the New York City Chatham Hotel where it was served as the signature dish in the early twentieth century.  Its creator, a chef named Lagasi, created it as part of a contest, winning a small amount of money and creating the hotel's signature dish.  In French, the word "divan" refers to a meeting place or great hall, and thus the name was chosen to imply a kind of continental elegance.

Gruyère cheese: Gruyère ( or ; ] , German: "Greyerzer") is a hard yellow cheese, named after the town of Gruyères in Switzerland, and originated in the cantons of Fribourg, Vaud, Neuchâtel, Jura, and Berne.  Before 2001, when Gruyère gained the "appellation d'origine contrôlée" (AOC, now AOP) status as a Swiss cheese, some controversy existed whether French cheeses of a similar nature could also be labelled "Gruyère" (French Gruyère style cheeses include Comté and Beaufort).

Mornay sauce: A Mornay sauce is a Béchamel sauce with shredded or grated Gruyère cheese added.  Some variations use different combinations of Gruyère, Emmental cheese, or white Cheddar.  A Mornay sauce made with cheddar is commonly used to make Macaroni and cheese.

Béchamel sauce: Béchamel sauce ( or ; French: "Béchamel" ] ), also known as white sauce, is made from a white roux (butter and flour) and milk.  It is, since the seventeenth century and on, one of the mother sauces of French cuisine.  It is used as the base for other sauces (such as Mornay sauce, which is Béchamel with cheese).

Bagel toast: Bagel toast (Hebrew: בייגל טוסט‎ , "Beygel Tost " ‎ ) is a sandwich commonly eaten in Israel.  It is composed of a pressed, toasted bagel filled with vegetables and cheese and is grilled on a sandwich toaster or panini press.  While the bagel is round with a hole in the center, it is unlike the typical American bagel in that it is made from a different dough with sesame seeds. Bagel toast is generally filled with tzfatit, feta, white, or yellow cheese, green olives, corn, tomatoes, onions, dressing, and pizza sauce, or a spicy sauce.

Gruyère (disambiguation): Gruyère is a hard yellow cheese made from cow's milk, named after the town of Gruyères

Cheddar sauce: Cheddar sauce, cheddar cheese sauce, or cheese sauce is a traditional sauce used in English cooking.  The sauce is based upon white sauce, which is known as one of the 'mother sauces' and cheddar cheese.  It is could be seen as an English equivalent of the French Mornay sauce (itself a variant of Béchamel sauce traditionally mixed with half Gruyère and half Parmesan).  The sauce is made by adding an amount of cheddar cheese to white sauce and then spiced using English mustard, Worcestershire sauce and pepper among other ingredients.

Kashkaval: Kashkaval is a type of yellow cheese made of cow milk (kashkaval vitosha), sheep milk (kashkaval balkan), or both (kashkaval preslav).  The name is derived from the Italian caciocavallo (Romanian: "cașcaval" ; Bulgarian: кашкавал , ] ; Macedonian: кашкавал , ] ; Serbian: качкаваљ or "kačkavalj" ; Albanian: "Kaçkavalli" ; Turkish: "kaşkaval/kaşar" ; Arabic: قشقوان‎‎‎ ‎ / "qashqawān").  In Albania, Bulgaria, Republic of Macedonia, Serbia and Romania, the term is often used to refer to all yellow cheeses (or even any cheese other than sirene).  In English-language menus in Bulgaria, "кашкавал" is translated as "yellow cheese" (whereas "sirene" is usually translated as "white cheese" or simply "cheese").

Veal Orloff: Veal Prince Orloff, veal Prince Orlov, veal Orloff, or veal Orlov (Russian: телятина "Орлов" , "telyátina Orlóv" or телятина по-орловски, "telyátina po-orlóvski"; French: "veau Orloff" or "veau Orlov") is a 19th-century dish of Russian cuisine, which was created by the French chef Urbain Dubois in the employ of Prince Orloff, former Russian ambassador to France.  The dish consists of a braised loin of veal, thinly sliced, filled with a thin layer of pureed mushrooms (duxelles) and onions (as soubise) between each slice, and stacked back.  It is then topped with Mornay sauce (bechamel sauce with cheese) and browned in the oven.

Korycinski: Koryciński, also known as "swojski" (homemade), is a hard yellow cheese made from cow's milk, named after the village of Korycin in Poland, and made in the Podlaskie Voivodeship in eastern Poland.  It is considered to be the oldest Polish yellow cheese.

Supporting paragraphs: Mornay sauce Gruyère cheese
Answer: Gruyère cheese