Can I make this casserole ahead of time?
Yes. Assemble the casserole, cover, and refrigerate up to 24 hours before baking. Add 5–10 minutes to the bake time if starting from cold.
What can I use instead of corned beef or pastrami?
Smoked turkey, roast beef, or ham work well. Use the same total weight for consistent flavor and texture.
Can I substitute the rye bread?
Pumpernickel, whole wheat, or sourdough are acceptable, though rye provides the authentic Reuben flavor.
How do I know when the casserole is done?
Bake until the custard is set (a knife inserted in the center comes out clean) and the top is golden, about 45–50 minutes.
Can I scale this recipe?
Yes. Double the ingredients for a 9×13-inch pan; increase bake time by 10–15 minutes.