Cut off the thick bottom end of the lemongrass stem and finely chop the bottom 4 cm (the thick part).

Discard the rest.

Clean the mushrooms thoroughly and slice them thinly.

Rinse the scallion, remove the root, and slice it thinly at an angle.

Seed the chili and cut into thin slices.

Sauté the lemongrass in the oil over medium heat for a few minutes and add 3 dl of the bouillon, you can add the rest at the end if you think the soup is too thick.

Let it simmer for 5 minutes, then add the shrimp. When they are almost cooked after 2-3 minutes, add the mushrooms and peas.

Bring the soup to a boil, remove it from the heat, and season with fish sauce.

Serve sprinkled with chili and Thai basil.