This mixture contains raw egg yolks, which require cooking. The yolks add richness to the mixture and help the creamy cheese hold together inside baked pastas. If you're planning to serve a dollop of the filling over prepared pasta or on ricotta toasts, I recommend mixing the ricotta, lemon zest, basil, salt and pepper and whipping with a whisk to achieve an airy texture. Taste and adjust seasoning, then serve!