Tuna Sandwich

This is a very popular, quick, and affordable sandwich style commonly found in Chinese bakeries, convenience stores, and home kitchens — especially in Hong Kong, Taiwan, and mainland urban areas. 

It features creamy canned tuna mixed with mayonnaise, sweet corn, finely diced vegetables, and sometimes a touch of sweetness or umami from Chinese condiments, all packed between soft milk bread (or toast). 

The result is rich, mildly sweet-savory, and extremely comforting.

Ingredients (makes Ingredients (makes 4–6 sandwiches)Tuna filling

• Canned tuna in oil or brine — 2 × 150–185 g cans (drain well; oil-packed gives richer flavor)
• Japanese-style mayonnaise (Kewpie preferred) — 4–6 tbsp (adjust for creaminess)
• Sweet corn kernels (canned or frozen, thawed) — 100–150 g (≈¾ cup)
• Carrot — ½ small, very finely diced or grated
• Cucumber — ½ small, deseeded and very finely diced (optional, adds freshness and crunch)
• Onion — ¼ small, very finely minced (or red onion for milder taste)
• Hard-boiled egg — 1–2, finely chopped (optional, very common in Chinese versions)
• Light soy sauce — ½–1 tsp (adds subtle umami)
• Sugar — ½–1 tsp (balances saltiness and mimics bakery sweetness)
• Salt — pinch (to taste)
• Ground white pepper — small pinch
• Optional extras for Chinese bakery style:
  • 1–2 tsp oyster sauce or a pinch of MSG (for deeper savory note)
  • 1 tsp sesame oil (for aroma)

Bread & assembly

• Soft milk bread (Hong Kong-style Pullman loaf) — 8–12 thick slices (or Japanese shokupan/toast bread)
• Butter or margarine — 2–3 tbsp, softened (for spreading)
• Optional: sliced cheese, lettuce leaves, tomato slices (some modern versions add these)

Step-by-Step Instructions

1. Prepare the tuna filling
   • Drain the canned tuna very well (press with a fork or spoon to remove excess liquid — too much moisture makes the filling soggy).
   • In a medium bowl, flake the tuna with a fork until fine but not pasty.
   • Add mayonnaise, sweet corn, finely diced carrot, cucumber (if using), minced onion, chopped hard-boiled egg (if using), light soy sauce, sugar, salt, white pepper, and optional oyster sauce/MSG/sesame oil.
   • Mix thoroughly until everything is evenly coated and creamy. Taste and adjust: it should be mildly sweet, savory, creamy, with noticeable tuna flavor.
   • Cover and refrigerate 20–30 minutes (chilling firms it up and lets flavors meld — very important for bakery-style texture).
2. Toast the bread (optional but recommended)
   • Lightly toast the bread slices until just golden and fragrant (use toaster or oven at 160°C/320°F for 3–4 minutes).
   • This prevents the bread from becoming soggy too quickly and adds a pleasant contrast.
   • While still warm, spread a thin layer of softened butter or margarine on one side of each slice (this creates a moisture barrier).
3. Assemble the sandwiches
   • Place a generous amount (about 3–4 tbsp) of chilled tuna filling on the buttered side of one slice.
   • Spread evenly, leaving a small border around the edges.
   • Optional: add a slice of cheese, lettuce, or tomato for extra layers (common in modern Chinese versions).
   • Top with another buttered slice (buttered side facing the filling).
   • Gently press down. Trim crusts if you want the classic neat bakery look (optional).
4. Slice & serve
   • Cut the sandwich diagonally into 2 triangles (or into 3 long strips — very common in Chinese convenience stores).
   • Serve immediately at room temperature or slightly chilled.
   • Best enjoyed fresh, but can be wrapped tightly and refrigerated up to 4–6 hours (flavors deepen, but bread may soften).

Quick Tips for Best Result

• Texture balance → Finely dice vegetables very small — large chunks make the filling fall out.
• Mayonnaise choice → Kewpie (Japanese) is the most common in Chinese bakeries — it’s richer and slightly sweeter than Western mayo.
• Not too wet → Drain tuna extremely well and chill filling — prevents soggy bread.
• Bread → Soft, slightly sweet milk bread is ideal. If unavailable, use thick-cut white sandwich bread or brioche.
• Variations →
  • Add diced ham, imitation crab, or boiled egg whites for “deluxe” versions.
  • For spicier: mix in chili crisp or sriracha.
  • For lighter: use Greek yogurt + a little mayo instead of full mayo.
• Storage → Best eaten same day. If storing, wrap tightly in cling film and keep refrigerated — eat within 6–8 hours for best texture.

This sandwich is creamy, mildly sweet-savory, and incredibly satisfying — a true modern Chinese comfort classic.