Prepare the shrimp by making a shallow cut along the back, removing the vein if present, and trimming the legs. Chop cilantro roots and stems finely, and roughly chop the leaves. Slice the purple onion thinly.

Heat salad oil in a pot over medium heat. Add ground pork and chopped cilantro roots and stems, sauté briefly, then add the broth ingredients (kombu dashi, fish sauce, red chili, garlic) and shrimp. Cook until the shrimp are fully cooked.