Japanese Potato Layer Gratin Recipe (Jagaimo Kasaneyaki) with White Sauce

🥔 Jagaimo Kasaneyaki (Japanese Potato Layer Gratin)

Jagaimo Kasaneyaki is a cozy, Japanese-style gratin characterized by its elegant layers. While similar to a French Gratin Dauphinois or a classic casserole, the Japanese “Kasaneyaki” (layered and baked) method focuses on the beautiful “Mille-feuille” texture of the thinly sliced potatoes.

💡 Cooking Terms to Know

Kasaneyaki (重ね焼き): Ingredients are layered and baked.
- 👉 Oven-Baked Cheese Millefeuille Cutlets
Kasanemushi (重ね蒸し): Ingredients are layered and steamed (like the famous Napa Cabbage & Pork Belly Nabe).
- 👉 Pork Belly Napa Cabbage Mille-Feuille Nabe

Oven-Baked Cheese Millefeuille Cutlets — **Pork kasaneyaki**

Napa cabbage mille-feuille made in the microwave — **Pork kasanemushi**

🛒 Ingredients (Serves 2); Jagaimo Kasaneyaki

Ingredient	Quantity	Notes
Potatoes	200g	Sliced 2mm thin
Canned White Sauce	200g	Or homemade Béchamel
Shredded Cheese	30g	Pizza cheese or Gruyère
Salt	2g	For seasoning the layers
Fresh Parsley	10g	For a bright finish

👨‍🍳 Jagaimo Kasaneyaki Step-by-Step Instructions

1. Prep the Potatoes

Wash and peel the potatoes.
Use a mandoline slicer to get uniform 2mm slices. This ensures even cooking and a beautiful cross-section.

2. Pre-cook (The “Quick Soft” Method)

Place slices in a heat-resistant bowl and cover with water.
Cover loosely with plastic wrap and microwave at 600W for 2 minutes.
Pro Tip: Drain well and pat dry. Removing excess water prevents the white sauce from becoming runny!

3. Season and Layer

Once cool enough to handle, sprinkle the salt evenly over the slices.
In a greased baking dish, create the layers: Potatoes → White Sauce → Potatoes.
Note: Don’t worry about spreading the sauce perfectly; it will naturally settle and bubble through the layers as it heats.

4. The Cheesy Finish

Top generously with shredded cheese.
If using frozen cheese, let it thaw slightly so it melts evenly and browns beautifully.

5. Bake

Place in a 250°C (480°F) oven.
No preheating required! Bake for approximately 20 minutes until the top is golden brown and bubbling.

6. Garnish

Finely chop the fresh parsley (kitchen scissors work great for this!) and scatter over the top before serving.

🌟 Pro Variations to Try

The Meaty Version: Add a layer of browned bacon bits or meat sauce between the potato layers for extra umami.
Homemade White Sauce: If you have time, try making it from scratch! Quick Ratio: Melt 20g butter, whisk in 20g flour, then slowly add 200ml milk. Season with salt, pepper, and a pinch of nutmeg. The secret is patience—don’t rush the milk!
Storage Tip: White sauce freezes beautifully. Make a double batch and keep it in portions for quick gratins or pasta dishes later.

Since we used Heinz White Sauce for that signature rich flavor, here is the nutritional breakdown and some healthy tips translated into English for you!

White sauce can be used not only for gratin but also for a variety of other dishes. Check out this article for many recommended recipes using white sauce! 👉 Recommended recipes using white sauce

📊 Nutrition Facts (Per Serving); Jagaimo Kasaneyaki

Based on standard values for Heinz Canned White Sauce and your specific recipe.

Item	Per Serving (Est.)	Total (2 Servings)
Energy (Calories)	238 kcal	476 kcal
Protein	6.5 g	13.0 g
Fat	13.2 g	26.4 g
Carbohydrates	23.5 g	47.0 g
Salt Equivalent	1.8 g	3.6 g

💡 Nutritional Highlights

Calories: At approximately 240 kcal per serving, this dish is incredibly satisfying as a side dish and pairs perfectly with a main protein like grilled chicken or steak.
Heinz White Sauce: Using 200g of a standard 290g can adds roughly 200 kcal total. Its characteristic richness comes from the high-quality butter and cream used in the base.
Sodium Note: Since Heinz sauce is already seasoned, the 2g of salt added in step (7) can be used sparingly. A light pinch is enough to keep it heart-healthy!

🍳 Level Up Your Dish!

To make this gratin even more balanced, try these quick additions:

Boost Vitamins: Add a layer of sliced onions or shimeji mushrooms. These add dietary fiber and a natural sweetness that complements the white sauce beautifully.
Iron-Rich Greens: Beyond the parsley garnish, try tucking some steamed spinach between the layers. It adds a vibrant pop of color and a boost of nutrients.

Heinz sauce is famous for its velvety texture, which makes the “fluffy” (hokuhoku) texture of the potatoes feel truly luxurious. I hope you enjoy this wonderful meal! (*ˊᵕˋ)♡‧₊

📖Related Link: Read the Japanese version of this article here! []　　

naokoan

Hi, I’m Naoko! I am a licensed Registered Dietitian in Japan, currently working in a hospital setting. My daily mission is to provide nutritious, healing meals to patients, ensuring that every dish supports their health and brings a smile to their face. My recipes are more than just cooking guides—they are built on scientific nutritional balance and clinical experience. Why I provide ingredients in grams (g): You might notice that all my recipes use precise gram measurements. This is because, as a dietitian, I believe that accuracy is the key to true health management. Whether you are tracking calories, managing salt intake, or simply want to recreate the exact flavor of a professional hospital kitchen, these measurements ensure your success and well-being. My Specialty: I specialize in high-pressure cooking and oven recipes that save time without sacrificing nutrition. My goal is to introduce the world to “Real Japanese Home Cooking”—dishes that are simple, budget-friendly, and body-friendly. I’m thrilled to share the wisdom of Japanese nutrition with you. Let’s cook our way to a healthier life!