Lasagna (singular, pronounced /la'zan.ja/), also lasagne (plural, pronounced /la'zan.jɛ/), is both a form of pasta in sheets (sometimes rippled, though seldom so in Italy) and also a dish, sometimes named lasagne al forno (meaning "oven-cooked lasagne") made with alternate layers of pasta, cheese, and often ragù (a meat sauce) or tomato sauce. While it is traditionally believed to have originated in Italy, the recipe was also featured in the first cookbook ever written in England., the claim is far from universally accepted (see the much earlier Roman use of "lasanum" below). The Italian embassy in London particularly speaks out against such theories.The word "lasagna" is derived from the Greek word "lasanon" meaning chamber pot. The word was later borrowed by the Romans as "lasanum" to mean cooking pot. The Italians then used the word to refer to the dish in which what is now known as lasagna is made. The word lasagna or lasagne (plural) now simply applies to the food itself. Most English-speaking people follow the Italian usage and use the plural "lasagne" to refer to both the dish and the pasta, but Americans commonly use the singular "lasagna".Various recipes call for several kinds of cheese, most often ricotta and mozzarella. The classic Lasagne alla Bolognese uses only Parmigiano Reggiano. Many recipes also add bechamel sauce (besciamella).A variant is Lasagne verde (green lasagne) which is the normal egg pasta with spinach added. Other variations include vegetarian or seafood versions of the dish.