Step 1

Bring a large pot of water to a boil for your pasta. Add salt, about 1 tsp per one liter of water.

Step 2

In a mortar and pestle, pound together lemongrass, galangal, lime leaves and Thai chilies until there are no more big chunks. It should resemble a fine crumble.

Step 3

In a wok or a large sauté pan, cook off the shrimp just until they’re done. Remove and set aside; do not clean the wok.

Step 4

Drop your spaghetti into the boiling water, set the timer for 1 minute LESS than the cooking time indicated on the package. Immediately start cooking your sauce once your pasta is dropped. (With this timing, your sauce should be done before the pasta is done. But if it is not, not a problem, just drain the pasta and set it aside until ready to use.)

Step 5

In the same wok, saute onion over medium heat for a couple of minutes until they’re translucent.

Step 6

Add the mushrooms and a little splash of fish sauce, then cook for a minute.

Step 7

Add herbs paste and quickly toss it in the oil, then add the tomatoes. Break up the tomatoes with your spatula into small chunks.

Step 8

Add chili paste and fish sauce, and simmer for a few minutes until the sauce is thickened.

Step 9

If the pasta is not yet done, just turn off the heat and wait for the pasta.

Step 10

Once the spaghetti is done, add it to the sauce—I like to use tongs and add move the pasta directly from the pot to the wok, no need to drain in the colander (less dishes to do!). This way you also get more of the starchy pasta water transferred into the sauce, which helps thicken the sauce slightly. If you’re going to drain the pasta, be sure to save a cup of pasta water in case you need it.

Step 11

Add shrimp back in and and toss everything in the sauce for 1 more minute, adding more pasta water if you need more liquid. You can make this as dry or as saucy as you like. I prefer it on the dryer side.

Step 12

Off the heat, then stir in lime juice and cilantro. Taste and adjust with more lime juice/fish sauce as needed.

Step 13

Serve with grated parmesan if desired.

Step 14

Enjoy!