Description
Cozy, cheesy, and wildly comforting—this Corned Beef Au Gratin Potato casserole stacks tender potatoes with savory corned beef and a creamy cheddar sauce. It’s weeknight-friendly, crowd-approved, and even better the next day.
Ingredients
3 lbs potatoes, peeled and thinly sliced (Russet or Yukon Gold)
1 lb corned beef, shredded (deli-sliced, canned, or pre-cooked)
2 cups shredded cheddar cheese (or cheddar + Gruyère blend)
2 cups milk (or 1 1/2 cups milk + 1/2 cup cream for extra richness)
3 tbsp butter
2 tbsp cornstarch (gluten-free thickener)
1 tsp salt (reduce if your corned beef is very salty)
1/2 tsp black pepper
Optional: 1/2 tsp smoked paprika or 1 tsp Dijon mustard (for extra flavor)
Optional garnish: chopped parsley or green onions
Instructions
1. Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish.
2. Slice potatoes evenly (about 1/8-inch thick). Parboil in salted water for 5–7 minutes until just barely tender. Drain well.
3. Make the sauce: In a saucepan, melt butter over medium heat. Whisk cornstarch into 1/2 cup of the cold milk until smooth, then whisk that into the pan.
4. Slowly whisk in the remaining milk. Simmer 3–5 minutes, stirring often, until lightly thickened.
5. Turn off heat. Stir in shredded cheese until fully melted and smooth. Taste and adjust pepper/salt (go easy—corned beef can be salty).
6. Assemble: Layer half the potatoes, then half the corned beef. Pour over half the cheese sauce. Repeat layers, finishing with sauce on top.
7. Cover with foil and bake 30 minutes. Remove foil and bake 15–25 minutes more, until bubbling and golden on top and potatoes are fork-tender.
8. Rest 10–15 minutes before slicing. Garnish with parsley or green onions and serve.
Notes
Salt check: Corned beef varies a lot—taste yours first and reduce added salt if needed.
Crunch upgrade: Sprinkle 1/3 cup panko on top (use gluten-free panko if needed) during the last 15 minutes.
Make-ahead: Assemble up to 2 days ahead, cover, and refrigerate. Add 5–10 minutes bake time if baking cold from the fridge.
Nutrition
- Serving Size: 1 serving (about 1 1/4 cups)
- Calories: 522 kcal
- Sugar: 4g
- Sodium: 1022mg
- Fat: 29g
- Saturated Fat: 16g
- Unsaturated Fat: 12g
- Trans Fat: 0g
- Carbohydrates: 44g
- Fiber: 4g
- Protein: 26g
- Cholesterol: 105mg