How To Thaw A Frozen Casserole Quickly. If this is a continual problem for you, try adding oil or butter to the water as it boils the first time. The only thing is remembering to do it in advance in preparedness for next morning’s breakfast or lunch, or whatever.

Instead, you should place your frozen casserole in the refrigerator and let it thaw overnight. After the casserole has defrosted, it's then time to place it in the oven for the reheating step. The first thing to be mindful of, as i mentioned before, is allowing your frozen bacon to thaw overnight in your refrigerator.