Hi there! I’m Cassandre, and today on Caramel Loafing, I'm thrilled to show you how to recreate one of Japan's most iconic convenience store breakfasts: the classic Japanese Egg Salad Sandwich (卵サンド).Plus, I'll share my secret for making your very own Japanese-style mayo from scratch!
If you've ever enjoyed an egg salad sandwich, you know it's a simple yet timeless choice for breakfast or lunch. But did you know that egg salad sandwiches can taste vastly different depending on where you are in the world? It largely comes down to two key factors: the type of mayonnaise used and the ratio of egg whites to yolks.
With this easy Japanese Egg Salad Sandwich recipe, you can perfectly recreate that famous convenience store taste right at home—the beloved Konbini Tamago Sando. To achieve that signature flavor, using Japanese mayonnaise is essential. The most famous brand, Kewpie, is celebrated for its rich, tangy, slightly sweet taste with a distinct savory umami note. If you can't find Japanese mayo at your local grocery store, don't worry—I'll show you exactly how to make your own authentic Japanese-style mayonnaise that tastes just like the real deal!
Fun Fact: Did you know that mayonnaise originally evolved from classic French aioli? While this Japanese version offers a distinct flavor profile from its traditional French counterpart, if you're curious to explore more, be sure to check out our Classic French Aioli Recipe here: Œufs Mimosa.
More Recipes to Explore:
Craving other deli classics? Try our: New York Deli-Style Tuna Salad Sandwich, the iconic American BLT Sandwich, or crispy and juicy Japanese Pork Katsu Sandwich. For a touch of elegance: Vienna Bread or a fresh Caesar Salad.
Japanese Egg Salad Sandwich Recipe
Ingredients
Yields: 2–3 sandwiches. You'll only use a portion of the Japanese mayo for the egg salad; store any remaining mayo in the fridge and consume within 2–3 days for optimal freshness.
☞ Japanese-Style Mayo
- 1 fresh egg yolk, room temperature
- 1 tsp mustard (about 16.5g / 0.58oz)
- 1/2 tsp salt (about 2.5g / 0.09oz)
- 1 tsp sugar (about 7.5g / 0.26oz)
- 1/4 tsp dashi powder (about 1g / 0.04oz)
- 1 tbsp rice vinegar (about 9.5g / 0.33oz)
- 100–110ml grapeseed oil
☞ Egg Salad Sandwich
- 5 eggs, room temperature
- 3–4 tbsp Japanese mayo (about 32.5–43g / 1.15–1.52oz)
- A pinch of salt
- 1–2 tsp sugar (about 3.5–7g / 0.12–0.25oz)
- 2 tbsp (or more) unsalted butter, softened
- 4 slices milk bread
Instructions
How to Make Japanese-Style Mayo
- In a mixing bowl, whisk together the egg yolk, mustard, salt, sugar, and dashi powder until the mixture is smooth and well combined.
- Add the oil in three small spoonfuls, whisking well after each addition to start the emulsion.
- Continue to drizzle in the remaining oil slowly while whisking constantly, until fully emulsified and thick.
- Stir in the rice vinegar, then taste and adjust seasoning as needed.
- Transfer the mayo to a container, cover with plastic wrap, and store in the fridge. Use within 2–3 days for best flavor.
How to Make the Egg Salad Sandwich
- Bring a pot of water to a boil. Carefully lower the room temperature eggs into the boiling water using a spoon to prevent cracking. Boil for 12 minutes.
- Meanwhile, prepare a large bowl of ice water. Once cooked, immediately transfer the eggs to the ice bath for 10 minutes to cool them completely.
- To crack and peel the eggs: gently tap both ends, roll them lightly, and peel under running water if necessary.
- Slice the eggs in half and separate yolks from whites.
- Roughly chop 2.5 egg whites into coarse pieces and set aside.
- In a separate bowl, mash the yolks with the Japanese mayonnaise, salt, and sugar using a fork until smooth. Gently fold in the chopped egg whites.
- Spread a thin layer of softened butter on both slices of bread. Pile a generous layer of egg salad on one slice. Top with the other, trim the crusts, and cut in half. Serve immediately!
Watch the full step-by-step video tutorial here: Japanese Egg Salad Sandwich / 7-11 Style Konbini Breakfast
FAQs & Expert Tips for Perfect Japanese Egg Salad Sandwiches
Even a simple sandwich like this has a few pro tips to get it just right. Here’s what you need to know to make your Konbini Tamago Sando perfectly at home.
How long does homemade Japanese mayonnaise last? Can I use olive oil instead?
Homemade Japanese mayonnaise contains fresh raw egg yolk and no preservatives, so it’s best to keep it refrigerated and use it within 3 days. Always use clean utensils and seal it tightly to keep it fresh.
As for the oil, olive oil can be used, but its strong flavor — even in extra virgin — can overpower the subtle taste of the mayonnaise. If you do try it, go for a mild, light olive oil.
Traditionally, neither Japanese nor French-style mayonnaise incorporates olive oil. However, in certain regions, olive oil mayonnaise is a distinct specialty—for instance, Spanish Salsa Mahonesa, which boasts a richer color and flavor, along with a characteristic fruity bitterness from the oil. In Spain, this type of homemade mayonnaise is a delightful accompaniment to dishes like potato salad (ensaladilla rusa), stuffed eggs (huevos rellenos), seafood, and various vegetables.
Can I substitute American mustard for Japanese mustard?
Yes, you can — just know the taste will be a bit different. Since this recipe aims to replicate a true Japanese convenience store egg salad, using Japanese-style mustard helps keep it authentic. But substitutions are fine!
Japanese mustard (often made with mustard seeds or wasabi) has a milder, more balanced flavor that’s perfect for Asian dishes. In contrast, American mustard, commonly used on hot dogs or burgers, has a more pronounced kick. If substituting, use a smaller amount or mix it thoroughly with the egg salad to balance the heat.
Can I use other dashi powder brands or homemade dashi?
Absolutely. Any brand or homemade version that gives you a similar umami flavor works well. Whether you buy dashi powder or make your own blend with bonito or kombu, it all helps add depth to your mayonnaise.
What rice vinegar and mustard brands work best?
We used common Japanese rice vinegar and mild Japanese mustard for this recipe. If you can’t find them locally, a mild white rice vinegar and smooth yellow mustard without extra heat are good substitutes.
Can I use white vinegar instead of rice vinegar?
Yes, but keep in mind that white vinegar is sharper and more acidic. Use a little less and add a pinch of sugar to mellow it out if needed.
Why Japanese Mayonnaise? Can I Use Regular Mayonnaise Instead?
The unique flavor of this egg salad sandwich really depends on Japanese-style mayonnaise, which is richer and more balanced in sweetness and tang thanks to the rice vinegar. If you can’t find it, make your own with the recipe above!
Japanese mayonnaise (Kewpie) is known for its high egg yolk content and distinctive rice vinegar taste — perfect for tamago sando. By comparison, typical American mayonnaise brands are oilier and less tangy, but you can definitely use what you like best.
What if I make too much egg salad?
If you’re worried about leftovers, just cut the recipe in half. Or enjoy any extra egg salad with fresh greens, whole-grain crackers, or as a chilled side dish. It’s best eaten within two days for peak flavor.
Should I really use more yolks than whites?
Yes! That’s what makes this egg salad so creamy and smooth. The secret to the famously “melt-in-your-mouth” texture of Japanese convenience store egg salad sandwiches is a higher yolk-to-white ratio.
How long can the egg salad be stored? Will it get watery?
It’s best to finish it within two days. When storing, cover the surface with a paper towel before sealing to help absorb excess moisture.
Once assembled, wrap the sandwich tightly in plastic wrap and enjoy within 3 hours. If you need to pack it for later, store the bread and filling separately and put it together right before eating.
What bread is best for this sandwich?
A soft, fluffy milk bread (shokupan) is absolutely perfect for this style of sandwich. If you can’t find milk bread, use thick-sliced white bread — just skip toasting it so it stays nice and tender.
How long does homemade mayonnaise keep?
Keep your homemade mayonnaise refrigerated and use it within 3 days. Always use clean utensils and keep it tightly sealed. You can portion it into small containers to avoid contamination each time you scoop some out.
Since both mayonnaise and egg salad are high in fat and protein, it's crucial to always keep them chilled—especially in warmer weather—to prevent spoilage.