Menbosha (Deep-Fried Shrimp Toast Cubes)

Variations

• Cantonese ha dor si (蝦多士): the filling goes on one slice, gets a scattering of sesame seeds, and is fried on that side only. It is the cha chaan teng standard and is cut into triangles. Not sandwiched, so the outside is far crisper and the filling thinner.
• The Korean-Chinese cube: what this recipe follows, and how ko.wikipedia describes it — filling between small squares of bread. This is the form Shandong immigrants brought over.
• A little pork fat in the filling: a tablespoon of fatback or lard makes it noticeably juicier. Restaurants commonly do this; shrimp alone dries out easily.
• In an air fryer: sprayed with oil, 190°C for 8-10 minutes. It colours, but there is no fried layer. Bread absorbing oil is the texture of this dish, so cutting the oil makes it a different food (deep-frying).
• Other than shrimp: white fish or chicken breast work, but bind less well, so increase the starch slightly. Shrimp's sweetness is half the dish, so a substitution costs a lot.
• Chinese frying and dim sum in the same family: tangsuyuk and guobaorou also build crispness by frying twice, and har gow and siu mai steam much the same shrimp filling. For Korean-Chinese cooking, jjajangmyeon and jjamppong are already here.

Tips

• Oil temperature is the whole dish. With no batter, temperature is the only variable you control. Below 150°C the bread drinks oil like a sponge and goes soggy; above 190°C the outside darkens before the shrimp inside is cooked. Frying at 160°C then 180°C is how you thread that gap (deep-frying, heat control).
• Day-old bread is better. Drier bread takes up less oil. With a fresh loaf, spread the squares out for half an hour or dry them a few minutes in a very low oven.
• Chop the shrimp coarsely, by knife. A processor breaks the protein down completely and you get fishcake texture. Mixing coarse and fine is the answer: the fine part binds, the coarse part gives you something to bite.
• Egg white only, no yolk. The white's protein sets in the heat and holds the filling together; the yolk is mostly fat and loosens it (cooking eggs).
• Stir in one direction to build stickiness. Salt helps the shrimp's muscle protein dissolve and the mixture turns tacky. Without that tack, the filling separates from the bread in the oil (salt and seasoning).
• Starch is there to hold moisture. One tablespoon is plenty; more and it turns rubbery (thickening sauces).
• Fry the sides standing up. This dish has four cut faces. Left flat, the top and bottom brown while the sides stay white bread, still holding oil (browning).
• Keep the filling off the outside. Shrimp squeezing out breaks away in the oil and burns, and those burnt bits stick to the next batch. Push it back in before you seal (wrapping and sealing).
• Drain on a rack. On kitchen paper, steam is trapped below and only the bottom face goes soft. That rule applies to frying generally.
• Use a high-smoke-point oil. You are taking it to 180°C, so no sesame or olive oil. Sesame oil belongs in the filling, one teaspoon, for aroma (cooking oils).
• Eat it at once. As it cools the bread reabsorbs oil and softens, and the contrast that makes the dish is gone. To reheat, use an air fryer or a 180°C oven for three or four minutes, not a microwave (serving temperature, reviving leftovers).
• They can be assembled and frozen. Freeze them raw and separated, then fry from frozen at 160°C for a little longer (freezing and thawing).