Make the sauce by combining the oyster sauce, fish sauce, sugar, water and shrimp paste. Stir to dissolve the sugar.

Pound garlic until chunky. Remove all but about 1 clove’s worth from the mortar. To the garlic in the mortar, add peppercorns, and cilantro stems and pound into a paste.

Dry the shrimp well with a paper towel, and if you’re leaving the tail on be sure to dry the tail extra carefully as water can collect there and cause a lot of splattering in the pan.

In a wok over high heat, add enough oil to coat the bottom. Once the oil is very hot, lay the shrimp down in one layer; you will need to do this in 2 batches. Let the shrimp sear until at least halfway cooked and slightly browned on the underside. Flip and cook the other side just until done (timing will depend on the size of the shrimp, but it should take no more than a few minutes total). Remove the pan from the heat and take out the shrimp, leaving all the oil behind. Repeat with the other half.

Allow the pan to cool for a minute, then add the chunky garlic and turn the heat back on to medium low. Add more oil if needed, then saute the garlic for about 2 minutes or until softened and the edges start to turn golden. Add the herb paste and saute for 15-20 seconds.

Turn the heat up to medium and add the cooked shrimp including all the collected juices. Add the sauce mixture, then toss for about 30 seconds to mix and reduce the sauce slightly.

Plate and garnish with chopped cilantro and/or green onions and/or fried garlic, if desired. Serve with jasmine rice.