French Onion Potato Bake – A Creamy, Cheesy Casserole with Deep Caramelized Flavor

🎉 Introduction

When you’re in the mood for comfort food that feels fancy but familiar, this French Onion Potato Bake is the answer. Imagine tender layers of thinly sliced potatoes smothered in a deeply flavorful French onion-style sauce, topped with melted cheese, and baked until golden and bubbling.

It’s hearty, rich, and satisfying—just like a cross between French onion soup and scalloped potatoes. This bake is the perfect side dish for roast dinners, holiday feasts, or even as a cozy vegetarian main. Once it’s on the table, don’t expect leftovers!

🧰 Equipment Needed

• 9×13-inch baking dish
• Large skillet or sauté pan
• Mandoline or sharp knife
• Cutting board
• Large mixing bowl
• Cheese grater
• Measuring cups and spoons
• Aluminum foil

🛒 Ingredients

🥔 Vegetables

• 2 lbs Yukon gold potatoes (or russet), thinly sliced
• 2 large yellow onions, thinly sliced
• 2 cloves garlic, minced

🧂 Spices & Pantry

• 1 tbsp all-purpose flour
• 1 tsp salt
• ½ tsp freshly ground black pepper
• ½ tsp thyme (fresh or dried)
• ¼ tsp smoked paprika (optional)

🧈 Oils, Butters & Broths

• 3 tbsp unsalted butter
• 1 tbsp olive oil
• 1½ cups beef broth (or vegetable broth for vegetarian)
• ½ cup heavy cream

🧀 Dairy

• 1 cup shredded Gruyère cheese
• ½ cup shredded mozzarella or fontina
• ¼ cup grated Parmesan

👩‍🍳 Directions

Step 1. Caramelize the Onions

1. In a large skillet, heat olive oil and butter over medium heat.
2. Add thinly sliced onions and a pinch of salt.
3. Cook, stirring frequently, for 25–30 minutes until golden brown and caramelized.
4. Add garlic and cook for 1 more minute.

Step 2. Make the Sauce

1. Sprinkle flour over caramelized onions and stir to coat.
2. Cook for 1 minute to remove raw flour taste.
3. Slowly pour in beef broth, whisking constantly to prevent lumps.
4. Add thyme, smoked paprika (if using), salt, and pepper.
5. Bring to a simmer and cook for 3–5 minutes until slightly thickened.
6. Stir in heavy cream and remove from heat.

Step 3. Prep the Potatoes

1. Thinly slice the potatoes using a mandoline or sharp knife (about ⅛-inch thick).
2. Place slices in a large bowl of cold water to remove excess starch, then drain and pat dry.

Step 4. Assemble the Casserole

1. Preheat oven to 375°F (190°C).
2. Grease a 9×13-inch baking dish.
3. Layer half of the potatoes in the dish.
4. Spoon half of the onion mixture over the potatoes.
5. Sprinkle with half of the Gruyère and mozzarella.
6. Repeat layers with remaining potatoes, onion sauce, and cheese.
7. Top with Parmesan.

Step 5. Bake Until Golden

1. Cover tightly with foil and bake for 40 minutes.
2. Remove foil and bake for another 20–25 minutes until top is golden brown and bubbly.
3. Let sit for 10 minutes before serving to set.

🍽️ Servings & Timing

• Servings: 6–8
• Prep time: 30 minutes
• Cook time: 65 minutes
• Total time: ~1 hour 35 minutes

🧊 Storage & Reheating

• Refrigerator: Store leftovers covered in the fridge for up to 4 days.
• Freezer: Freeze tightly wrapped portions for up to 2 months.
• Reheat: Microwave individual portions or bake at 350°F for 20 minutes until heated through.

🥄 Variations

• Meaty Option: Add cooked bacon or sausage between layers.
• Vegan Version: Use vegan cheese, plant-based cream, and caramelize onions in olive oil only.
• Herbaceous: Add rosemary, sage, or bay leaf to the onion sauce for extra depth.
• Spicy Twist: Add a pinch of crushed red pepper flakes or top with chili crisp.
• French Onion Soup Inspired: Top with croutons before baking for added crunch.

❓ 10 FAQs

1. Can I use different potatoes?
Yes—Yukon Golds are creamy and hold their shape, but russets work well too.

2. What’s the best cheese substitute for Gruyère?
Fontina, Emmental, or sharp white cheddar are excellent substitutes.

3. Can I make this ahead of time?
Yes—assemble the day before, refrigerate, then bake when ready.

4. Is this dish gluten-free?
It can be—just replace the flour with cornstarch or gluten-free flour.

5. Can I make it vegetarian?
Absolutely! Use veggie broth instead of beef broth.

6. Why soak the potatoes?
It removes excess starch, helping the bake stay firm, not gummy.

7. Do I have to use cream?
No, you can substitute half-and-half or whole milk, but it may be less rich.

8. How thin should the potatoes be sliced?
About ⅛ inch for best texture—thin enough to cook evenly, thick enough to hold their shape.

9. Can I use pre-cooked or leftover potatoes?
Yes, but reduce baking time by 15–20 minutes since they’re already cooked.

10. What can I serve with this bake?
It pairs beautifully with roasted chicken, grilled steak, green salad, or steamed vegetables.

🏁 Conclusion

This French Onion Potato Bake is more than just a side dish—it’s a showstopper. With layers of creamy potatoes, golden caramelized onions, and gooey melted cheese, it’s hearty enough for a main and comforting enough to win over any crowd.

It’s an elegant twist on a classic casserole, and once you taste it, you’ll be making it for holidays, Sunday dinners, and cozy nights in.

Adam

French Onion Potato Bake – A Creamy, Cheesy Casserole with Deep Caramelized Flavor

When you’re in the mood for comfort food that feels fancy but familiar, this French Onion Potato Bake is the answer. Imagine tender layers of thinly sliced potatoes smothered in a deeply flavorful French onion-style sauce, topped with melted cheese, and baked until golden and bubbling. It’s hearty, rich, and satisfying—just like a cross between French onion soup and scalloped potatoes. This bake is the perfect side dish for roast dinners, holiday feasts, or even as a cozy vegetarian main. Once it’s on the table, don’t expect leftovers!

Print Recipe Pin Recipe

Prep Time 30 minutes mins

Cook Time 1 hour hr 5 minutes mins

Total Time 1 hour hr 35 minutes mins

Servings: 8 servings

Ingredients Equipment Method Notes

Ingredients

  

🥔 Vegetables

• 2 lbs Yukon gold potatoes or russet, thinly sliced
• 2 large yellow onions thinly sliced
• 2 cloves garlic minced

🧂 Spices & Pantry

• 1 tbsp all-purpose flour
• 1 tsp salt
• ½ tsp freshly ground black pepper
• ½ tsp thyme fresh or dried
• ¼ tsp smoked paprika optional

🧈 Oils, Butters & Broths

• 3 tbsp unsalted butter
• 1 tbsp olive oil
• 1½ cups beef broth or vegetable broth for vegetarian
• ½ cup heavy cream

🧀 Dairy

• 1 cup shredded Gruyère cheese
• ½ cup shredded mozzarella or fontina
• ¼ cup grated Parmesan

Equipment

• 9×13-inch baking dish
• Large skillet or sauté pan
• Mandoline or sharp knife
• Cutting board
• Large mixing bowl
• Cheese grater
• Measuring cups and spoons
• Aluminum foil

Method

 

Step 1. Caramelize the Onions

1. In a large skillet, heat olive oil and butter over medium heat.
2. Add thinly sliced onions and a pinch of salt.
3. Cook, stirring frequently, for 25–30 minutes until golden brown and caramelized.
4. Add garlic and cook for 1 more minute.

Step 2. Make the Sauce

1. Sprinkle flour over caramelized onions and stir to coat.
2. Cook for 1 minute to remove raw flour taste.
3. Slowly pour in beef broth, whisking constantly to prevent lumps.
4. Add thyme, smoked paprika (if using), salt, and pepper.
5. Bring to a simmer and cook for 3–5 minutes until slightly thickened.
6. Stir in heavy cream and remove from heat.

Step 3. Prep the Potatoes

1. Thinly slice the potatoes using a mandoline or sharp knife (about ⅛-inch thick).
2. Place slices in a large bowl of cold water to remove excess starch, then drain and pat dry.

Step 4. Assemble the Casserole

1. Preheat oven to 375°F (190°C).
2. Grease a 9×13-inch baking dish.
3. Layer half of the potatoes in the dish.
4. Spoon half of the onion mixture over the potatoes.
5. Sprinkle with half of the Gruyère and mozzarella.
6. Repeat layers with remaining potatoes, onion sauce, and cheese.
7. Top with Parmesan.

Step 5. Bake Until Golden

1. Cover tightly with foil and bake for 40 minutes.
2. Remove foil and bake for another 20–25 minutes until top is golden brown and bubbly.
3. Let sit for 10 minutes before serving to set.

Notes

🧊 Storage & Reheating
Refrigerator: Store leftovers covered in the fridge for up to 4 days.

Freezer: Freeze tightly wrapped portions for up to 2 months.

Reheat: Microwave individual portions or bake at 350°F for 20 minutes until heated through.

🥄 Variations
Meaty Option: Add cooked bacon or sausage between layers.

Vegan Version: Use vegan cheese, plant-based cream, and caramelize onions in olive oil only.

Herbaceous: Add rosemary, sage, or bay leaf to the onion sauce for extra depth.

Spicy Twist: Add a pinch of crushed red pepper flakes or top with chili crisp.

French Onion Soup Inspired: Top with croutons before baking for added crunch.

❓ 10 FAQs
1. Can I use different potatoes?
Yes—Yukon Golds are creamy and hold their shape, but russets work well too.

2. What’s the best cheese substitute for Gruyère?
Fontina, Emmental, or sharp white cheddar are excellent substitutes.

3. Can I make this ahead of time?
Yes—assemble the day before, refrigerate, then bake when ready.

4. Is this dish gluten-free?
It can be—just replace the flour with cornstarch or gluten-free flour.

5. Can I make it vegetarian?
Absolutely! Use veggie broth instead of beef broth.

6. Why soak the potatoes?
It removes excess starch, helping the bake stay firm, not gummy.

7. Do I have to use cream?
No, you can substitute half-and-half or whole milk, but it may be less rich.

8. How thin should the potatoes be sliced?
About ⅛ inch for best texture—thin enough to cook evenly, thick enough to hold their shape.

9. Can I use pre-cooked or leftover potatoes?
Yes, but reduce baking time by 15–20 minutes since they’re already cooked.

10. What can I serve with this bake?
It pairs beautifully with roasted chicken, grilled steak, green salad, or steamed vegetables.

🏁 Conclusion
This French Onion Potato Bake is more than just a side dish—it’s a showstopper. With layers of creamy potatoes, golden caramelized onions, and gooey melted cheese, it’s hearty enough for a main and comforting enough to win over any crowd.

It’s an elegant twist on a classic casserole, and once you taste it, you’ll be making it for holidays, Sunday dinners, and cozy nights in.