I assembled the ingredients for this egg casserole with hashbrowns and sausage 48 hours in advance without any problems. However, since this is a perishable recipe, theu003ca href=u0022https://ask.usda.gov/s/article/How-long-can-I-keep-an-egg-strata-in-the-refrigerator-before-cooking-itu0022u003e USDA recommends cooking an egg casseroleu003c/au003e the morning after it's assembled. My advice is to use your best judgment.