The way to eat boxed lactone tofu is to steam it for about twenty minutes and then just chill it.

Gently run the tip of a knife along the four walls of the box and invert the tofu box onto a chopping board, and the white, tender tofu can be removed intact. Cut the tofu into 5-centimeter-square chunks, using a softer hand.

Heat the oil in a wok over medium heat until it's 70% hot. Place the chopped tofu in a dish with dry starch, and use your hands to pat the tofu so that the starch coats it evenly, and deep-fry the tofu in the wok. Make sure your hands are dry, otherwise they will stick and cause the tofu to break apart. Use a large spoon to slowly stir the tofu in the pan so it doesn't stick together. Remove the tofu cubes from the pan when they turn golden brown, drain off the oil and arrange on a plate, drizzle with the plum sauce. The golden tofu cubes are topped with the sweet plum sauce, which is really tempting.

What is called lactone tofu:

Boxed lactone tofu is a food product that is made from traditional tofu, mostly using gypsum and brine as coagulants, which is a complicated process, low yield, short storage period, and not easy for the human body to absorb. And the production of tofu with lactone gluconate as coagulant can reduce protein loss and improve water retention. It greatly increases the yield, and the tofu is white and delicate, shiny, with good taste and long storage time.

After adding gluconolactone to the box, it can be put into the box and made into boxed lactone tofu, which can be eaten or sold after stable molding. If you want to make slabs of tofu, you can press narrow and filter the water in the usual way.

The above content reference from the link: Baidu encyclopedia - lactone tofu