Ingredients
Equipment
Method
Make the Sardine Filling
- Heat neutral oil in a small pan over medium heat. Add the diced onion and a pinch of salt. Cook for 4 to 5 minutes, stirring occasionally, until the onion is soft and lightly golden. Do not rush this step. The onion needs to be fully cooked before the sardines go in. Raw onion in the filling produces a sharp bite that overpowers the fish.
- Add the sardines and all their tomato sauce to the pan. Add fish sauce, sugar, black pepper, and water. Stir and partially mash the sardines with the back of a spoon. They should break down into large flakes, not a smooth paste. Leave some texture. Simmer for 3 to 4 minutes until the sauce thickens and coats the fish. The filling is ready when it holds its shape on a spoon without running.
- Remove from heat. Taste and adjust black pepper. Bánh mì cá mòi is generously seasoned with black pepper. It should be clearly present in every bite.
Assemble
- Split each baguette lengthwise, cutting three-quarters through. Do not cut completely. Open the bread. Apply Vietnamese mayonnaise to both cut surfaces. This is the fat barrier. It seals the bread and prevents the warm sardine filling from making the crumb soggy.
- Spread pork liver pâté on the bottom half only.
- Spoon the warm sardine filling generously along the full length of the bread over the pâté. The filling should be warm when it goes in. A cold sardine filling loses the flavor intensity the black pepper and fish sauce produce when warm.
- Add Persian cucumber strips across the sardine filling. Add the drained đồ chua on top of the cucumber. Excess brine will make the sandwich soggy.
- Add cilantro in whole sprigs. Do not chop it. Add jalapeño slices. Two to three per sandwich is correct. Add three drops of Maggi Seasoning Sauce across the top. Finish with freshly ground black pepper. Close the sandwich and press down firmly. Serve immediately.
Notes
On the sardines: Canned sardines packed in tomato sauce are correct for this recipe. Not sardines in olive oil, not sardines in water. The tomato sauce is the cooking medium and the source of the flavor that ties the filling together. Any brand works but look for sardines packed tightly in a thick tomato sauce rather than a thin watery one. The thickness of the sauce determines the final texture of the filling.
On the mashing technique: Partially mash the sardines, not completely. The filling should have visible flakes of fish in a thick tomato sauce, not a smooth spread. Complete mashing produces a paste that sits flat in the sandwich. Partial mashing produces a filling with texture that holds its shape when the bread is pressed together.
On black pepper: Black pepper is the defining seasoning of bánh mì cá mòi. Use freshly ground pepper, not pre-ground. The amount in the recipe produces a clearly present but not overwhelming heat. Add more at the end if you prefer a stronger result. This is one sandwich where more pepper is almost always correct.
On Vietnamese mayonnaise: Vietnamese mayonnaise is the correct choice here. The recipe is on this site. If you do not have time to make it from scratch, Kewpie is the correct store-bought substitute. Do not use standard mayonnaise. The flavor profile is different enough to affect the finished sandwich.
On the pickles: The đồ chua recipe on this site produces the correct pickle for this sandwich. Make it at least 1 hour ahead. If you have a jar already made, use it. The pickles keep for 2 weeks refrigerated.
On make-ahead: The sardine filling keeps for 2 days refrigerated. Reheat gently in a small pan before assembling. Do not microwave. The filling dries out and loses its sauce texture when microwaved. Assemble the sandwiches to order.
On sourcing: Canned sardines in tomato sauce are available at every supermarket. Brunswick, King Oscar, and Chicken of the Sea all produce acceptable results. The brand matters less than the tomato sauce being thick and flavorful.