This sandwich takes cooked teriyaki chicken thighs and stacks them with pan-fried mushrooms, shredded lettuce, red onion, and honey-mustard on toasted bread. There is no mayo, no complicated sauce to make, and if the chicken is already cooked, the whole thing is ready in 10 minutes. It is a genuinely useful way to get a filling lunch or quick dinner on the table without starting from scratch.
What makes this version work
Two things carry this sandwich. First, the honey-mustard goes directly on the bread before the lettuce — that layer of leaves sits between the sauce and the warm chicken, which keeps the toast from turning soft while you build the rest of the sandwich. Second, the mushrooms are cooked hot and fast in a single layer rather than stirred constantly; they brown instead of steam, and that browning adds a savory depth that makes the filling feel more substantial. Skip the garnish — not worth the extra dish. Those two steps are what separate a good sandwich from a soggy one.
Troubleshooting
- Sandwich falls apart when you pick it up: The filling stack is probably too tall. When scaling up for guests, resist the urge to pile extra chicken into each sandwich — two thighs per sandwich is the limit before structural integrity goes. Cut each sandwich diagonally immediately after assembling so the halves are easier to handle.
- Mushrooms released a lot of water and taste bland: The pan was not hot enough before the oil went in, or the mushrooms were wet. Pat sliced mushrooms dry with a paper towel before they hit the skillet, and wait until the oil shimmers before adding them.
- Red onion flavor is overwhelming everything else: Soak the sliced rings in cold water for 5 minutes, then drain and pat dry. This pulls out a significant amount of the sharp bite without cooking the onion or losing the crunch.
- Bread went cold and lost its crispness before serving: Toast the bread in batches as close to assembly time as possible. If you are making multiple sandwiches for a group, keep finished toast in a single layer on a wire rack in a 200°F oven rather than stacking slices, which traps steam and softens them fast.
- Honey-mustard tastes flat against the teriyaki glaze: Store-bought honey-mustard varies a lot in sharpness. Stir in a small squeeze of fresh lemon juice or a few drops of white wine vinegar to sharpen it up before spreading.
Make-ahead notes
The cooked teriyaki chicken keeps well in an airtight container in the fridge for up to 4 days, making it easy to prep a batch on the weekend and pull sandwiches together on demand throughout the week. Slice the chicken just before assembling rather than storing it pre-sliced — whole thighs retain moisture better. The mushrooms can be cooked ahead and refrigerated for up to 2 days; reheat them in a dry skillet over medium heat for about 2 minutes to drive off any stored moisture before using. Do not assemble the sandwiches in advance. Once built, the bread softens quickly from the fillings, and there is no good way to recover it. If you are feeding a group, set everything out as components and toast the bread in the final few minutes before people sit down.
Chicken Teriyaki Sandwich (Ready in 10 Minutes!)
Ingredients
- 4 pieces boneless, skinless chicken thighs about 500g / 1.1lb total, cooked in teriyaki sauce and cooled slightly
- 6 pieces medium button mushrooms about 100g / 3.5oz, thinly sliced
- 1 tablespoon vegetable oil for pan-frying mushrooms
- 1 pinch salt as needed; for seasoning mushrooms
- 1 pinch pepper as needed; for seasoning mushrooms
- 5 leaves iceberg or cos (romaine) lettuce shredded
- 1 small red onion thinly sliced into rings
- 4 tablespoons honey-mustard sauce store-bought or homemade
- 4 slices thick-cut white or wholemeal sandwich bread toasted
Instructions
- Slice the chicken teriyaki into thin strips.
- Take a slice of toasted bread and spread 1 tablespoon of honey-mustard sauce evenly over the entire surface. Optionally spread another tablespoon on the top slice for extra flavour.
- Cover the bread with shredded lettuce.
- Arrange the chicken teriyaki strips on top of the lettuce.
- Pile the mushroom slices on top of the chicken.
- Top the mushrooms with onion rings.
- Cover with another slice of bread.
- Repeat to make another sandwich.
- Slice each sandwich diagonally into triangles and serve immediately while the bread is still warm and crisp.
Nutrition
Common questions
Can I use chicken breast instead of chicken thighs?
Yes, but the result will be drier. Chicken thighs hold moisture better under a teriyaki glaze and stay tender when sliced cold from the fridge; breast meat tends to go chalky once refrigerated. If you only have breast, slice it thicker to help retain some texture.
What bread works best if I want to make a lot of these at once?
A sturdy thick-cut sandwich loaf — white or wholemeal — is the most practical choice for a crowd because it toasts evenly and holds up under the fillings without splitting. Avoid anything with a very open crumb like sourdough, which lets the sauce soak straight through.
Can I use a different sauce instead of honey-mustard?
A teriyaki mayo works well — mix equal parts Japanese mayonnaise and store-bought teriyaki sauce. Avoid anything very acidic like a straight vinaigrette, which will make the bread go soft faster than honey-mustard does.
How do I keep the sandwiches warm if I am serving them to guests?
Assemble them and place on a wire rack set over a baking sheet in a 200°F oven for up to 10 minutes. Any longer and the lettuce wilts and the bread loses its crunch, so time this as the last step before serving.
Can the assembled sandwiches be wrapped and packed for lunch?
They travel reasonably well for up to about 2 hours if you wrap them tightly in parchment or foil and keep them cool. Pack the honey-mustard separately and spread it just before eating if you want the bread to stay as crisp as possible.
More recipes to try
- Authentic Japanese Chicken Teriyaki
- Sweet and Tangy Grape Chicken Salad
- Sizzling Street-Style Grilled Chicken Tacos
- Quick and Delicious Homemade Chinese Fried Rice
