Remove the head and shell of the shrimps and leave the tails intact.
Put in a bowl and season with salt and pepper. Set aside.
Cut the broccoli into bite size pieces. Discard the stem.
Heat water in a pot and blanch the broccoli for a minute then put in a strainer. Rinse in cold water and drain.
In an empty bowl, combine water, cornstarch, onions leeks, garlic, soy sauce, sesame oil and sugar. Stir until the cornstarch and sugar are dissolved.
Heat cooking oil in an empty pan and saute garlic until fragrant. Add the shrimps and saute for 3 minutes.
Add the broccoli and saute for another minute. Then pour the cornstarch mixture and stir. Simmer until the sauce is thick.
Turn off heat and serve hot!