Ingredient variations are the key differences in lasagna recipes, such as flat lasagna noodles versus ruffle-edged, plain tomato sauce, meat sauce or basil pesto, and meat or fish versus vegetables for the main filling between the layers of noodles.
Despite the number of viable ingredients with which lasagna is made, the technique of layering cooked ingredients between lasagna noodles within a casserole dish is consistent the world over. In times past, Italians of the Emilia-Romagna region used a white sauce, a bechemel, when preparing traditional Lasagna alla Bolognese. Today, a mixture of ricotta and Parmesan cheese serves the same function.
A minor difference in lasagna recipes is the use of eggs. Some recipes call for mixing eggs with Parmesan cheese and ricotta to help bind the ricotta and prevent the lasagna sauce from becoming too loose. Straining the ricotta is an option, if there are no eggs at hand.
The last noteworthy difference in lasagna recipes is that some use dry, boxed noodles, no-boil noodles or homemade noodles. The use of different kinds of lasagna noodles changes the overall prep time. No-boil noodles tend to require more sauce as they soak up more moisture during cooking time. Boxed noodles must be patted dry or set out upon towels to dry before use within the casserole or the excess water on them may make for a runny sauce.