You can't.
Butter crabs are not mass-produced by artificial means, but only natural variation of blue crabs. Because things are rare, the price is particularly high.
Only one of the average/kloc-0.000 blue crabs can only become a "butter crab", and it appears in the hottest June-August, so it is recognized as the best among blue crabs.
Crucially, the causes of butter crabs are very complicated, so far it is impossible to intervene artificially, resulting in a very rare number. Butter crabs are divided into primary, secondary and ointment. Top butter crabs can only be sold for 2000 yuan each, which is also sky-high. After all, things are rare!
How do I know if it's butter crab?
To choose delicious butter crabs, the best products come from Fuyong, Shajing, Liufushan and Baishizhou in Shenzhen. There is a little less butter crab oil in other places. Secondly, the joints of the crispy crab are golden yellow and the feet are swollen. Pressing the cover position with your hand will feel a little soft because the cream has completely evaporated. If you press it to make it hard, the paste is not used up. Finally, look at the crab noodles. Put the butter crab in the sun. Cover the surface of the crab with your palm. You can see if both sides of the crab shell are transparent. The more transparent the oil, the more oil.
The difference between butter crab and cream crab
The difference between butter crab and cream crab is that the butter on it can already see the oil. After cooking, the oil is liquid, and the oil has spread all over the crab, including its claws and various parts of its body. Therefore, butter crabs generally have a yellow light on their navel and claws, just like butter is about to flow out, and their bodies are full. Therefore, butter crabs must be frozen with ice water before steaming to prevent oil from oozing out during cooking. After all, the butter crab eats its oil, which is the essence.