A simple and delicious Onion Sandwich! We make this extra tasty with special tips and simple pantry ingredients. Don't forget to slice the onions very thin and be generous with the mayo. Enjoy ^_^
We love onions. We really love sweet onions. And we especially love sweet Maui onions! Use the sweetest onions you can find because onions are the focus of this wonderful sandwich.
Our onion sandwich is easy to assemble and doesn't require any cooking (just toasting). You only need 4 ingredients and 10 minutes.
An onion sandwich might sound strange, but once you make it, you'll understand our obsession with it. Because there are just 4 ingredients (plus salt), each ingredient really counts. So use the best you can get.
This sandwich is flavorful, so bright and light. I always feel happy after eating it.
Here's what you'll need:
- Bread - You can use any type of sandwich bread you have on hand. We usually use milk bread or soft white bread from local Japanese bakeries. Here in Honolulu I like to buy sandwich bread from Epi-Ya and Brug Bakery.
- Mayonnaise - Ideally Kewpie mayo.
- Parsley - Finely chopped
- Sweet onion - If you're in Hawaii, use sweet Maui onion. They are so delicious! Slice the onions as thin as possible. You can find sweet Maui onions at many supermarkets and farmers markets.
- Sea salt - Ideally Maldon salt which you can find at most supermarekts.
See recipe card for quantities.
Let's get cooking! Or rather, assembling...hahah ^_^
Spread half a tablespoon of mayonnaise on each slice of bread.
You can use more mayo if you like. But half tablespoon per slice is the minimum you should use.
Toast until golden.
We grew up with toaster ovens instead of a regular slot toasters. Not sure if it's a Hawaii thing or Asian thing, but I feel like most people here use toaster ovens.
We recently replaced our old toaster oven (which we had for over a decade!) with a Balmuda toaster and love it! It's a definite splurge but has been worth even penny.
Sprinkle the parsley on one slice of the bread. Make sure the parsley is finely chopped.
Arrange the thinly sliced onion evenly on top of the parsley.
Sprinkle the sea salt on top of the onions.
Cover the sandwich with the other slice of bread (make sure the mayo side is face down).
Press gently and slice the sandwich in half diagonally.
Eat warm and enjoy ^_^
Substitutions and Variations
Here are a few ideas to get you started:
- Butter - No mayo? No problem. Make this sandwich using good butter. When using butter, I skip the toasting step and just spread a generous layer of softened butter on fresh bread.
- Brioche - This sandwich is also really tasty with brioche! Here in Honolulu, we buy good brioche from Breadshop in Kaimuki.
- Cheese - Add a slice of good cheese!
- Black Pepper - Add a little fresh cracked black pepper to the sandwich. Add it the same time you add the sea salt. Just a little pepper. A little goes a long way
- Ham, turkey, or bacon - Meat is totally not necessary for this recipe. But if you want to add meat, you can slip in a few slices of ham, turkey, or bacon. I feel like bacon works best.
I recommend following the recipe as written your first time making it. And then feel free to experiment from there.
Make the onion sandwich right before you eat it. It will not keep. Ideally enjoyed within 5-10 minutes of assembly ^_^
I usually make this for a quick and easy lunch or snack. I make and devour it all while standing at the kitchen counter. Love it when the bread is still warm and toasty and the onions and crisp and cool. Super onolicious.
We want the onions slice as thinly as possible for this recipe. Layers and layers of super thin onions are what make this sandwich special. How to slice the onions extra thing without cutting yourself? Use a madoline!
Have you heard about the James Beard Onion Sandwich? That's the sandwich that inspired this recipe!
The James Beard version is fancier. The bread is cut into delicate rounds (perfect for afternoon tea or a cocktail party).
The sandwich sides are rolled in chopped parsley (as opposed to layering the parsley inside the sandwich).
And the assembled sandwiches are chilled for a few hours in the refrigerator before serving.
Yes! Don't underestimate how delicious lots of raw onions layered in a sandwich tastes.
Part of the magic is in using sweet onions and slicing the onions super thin.
It's crisp, fresh, and delicate. The mayo and sea salt rounds out the flavor and parsley adds another dimension. It's just so good. Don't forget to use good quality bread.
Yes. If you don't like parsley, just skip it. It will still be tasty.
Onion Sandwich Recipe
- Spread half a tablespoon of mayonnaise on each slice of bread.
- Toast until golden.
- Sprinkle the parsley on one slice of the bread.
- Arrange the thinly sliced onion evenly on top of the parsley.
- Sprinkle the sea salt on top of the onions.
- Cover the sandwich with the other slice of bread (mayo side face down).
- Press gently and slice in half diagonally.
- Eat warm and enjoy! ^_^
Looking for other recipes like this? Try these: