For the lasagna filling, you may use béchamel, which is a delicious, rich sauce, or you may use ricotta, a slightly tangy soft Italian cheese, but you should NOT be using cottage cheese, which is a sad relic of mid-century diet platters. Cottage cheese and ricotta may have a similar appearance, but they're not at all the same thing. While both cheeses are white and soft, Chowhound points out that cottage cheese is much lumpier and wetter than ricotta. It is also significantly higher in sodium, if admittedly lower in fat (hence its enduring popularity with diet creators, if not the dieters who've been forced to eat the stuff). Unless you're a fan of soggy lasagna, they advise steering clear of using cottage cheese in this dish.
If you are on a strict calorie budget, however, and are wanting to pare every last fat gram from your lasagna, in this case cottage cheese may be called for. If you absolutely have to make such a sacrifice in the name of good nutrition, though, you should at least strain or blend the cottage cheese to give it a slightly more ricotta-like texture, and you might also want to cut back on any salt in the recipe.
