Cut pork belly into 1" pieces. Cut daikon radish, zucchini, potato, and onion into 1/2" chunks.
Cook noodles according to packaging instructions, until al dente. Immediately rinse under cold water and drain - this will keep the noodles chewy and bouncy.
Brown pork belly pieces over medium high heat in 1 tbsp of neutral oil for 2-3 minutes to render out some fat.
Add vegetable chunks into pan of pork belly pieces and sauté until softened (3-4 minutes). Season with kosher salt and black pepper.
In your pan, create a small well in the center of your pork and vegetable chunks. Add black bean paste and fry for 2 minutes before mixing well with the pork and vegetable chunks.
Add water. Cover and simmer on medium low heat for 8-10 minutes (or until vegetables are tender). Meanwhile, in a separate bowl, mix cornstarch, sugar, and water into a slurry.
Add slurry into sauce and stir until thickened. Season with salt and pepper to taste. Pour sauce over noodles, mix, and enjoy!
Video
Notes
Pork Tips - This recipe is made traditionally with pork belly (or pork shoulder). Cut the pork belly into 1" pieces, keeping mind that pork tends to shrink down once it is cooked. When cooking the pork, make sure it turns golden brown and you can see that the fat has rendered out of the pork - you will be saute-ing the vegetables in this fat, which will add more flavor to your Jajangmyeon sauce.Vegetable Tips - I used zucchini, daikon radish, and potatoes - I like this combination because while similar, they're different in softness and texture. The flavors of all three are mild enough to pair nicely with the sauce, which is on the saltier side. Cut the vegetables into similar sizes/shapes so they cook evenly. You can substitute or add other mild vegetables like squash, cabbage, or carrots.Noodles - Use fresh Korean wheat noodles for the most authentic version of this dish. If you can't find Korean wheat noodles, you can substitute for fresh udon or a thick, dried noodle of your choice. Once you have cooked your noodles according to the package directions, immediately rinse them under cold water - this will stop the cooking process so your noodles remain perfectly al dente. You can also toss the noodles in a little bit of neutral oil to keep them from sticking together while you prepare the Jajangmyeon sauce."Fry" the Korean Black Bean Paste - When adding the black bean paste, create a well in the center of the pork and vegetables and "fry" the paste for 2 minutes BEFORE mixing it in. "Frying" the paste helps caramelize and render out some of the flavors of the fermented paste - the black bean paste is very strong and 'raw' straight out of the jar.Storage - If you have leftover Jajangmyeon, you can store them in an airtight container in the refrigerator for up to 3 days. The noodles will be stuck together when reheating but the flavor will still be delicious! I would microwave them quickly with a little bit of water to loose them up.If you have leftover noodles and sauce that have not been mixed together, I highly recommend storing them separately in their own airtight containers for up to 3-4 days.You can easily make Jajangmyeon sauce in advance! Once the sauce is made, store in an airtight container for up to 3-4 days in the refrigerator. When ready to cook, heat up the sauce in a pan and cook the noodles according to package directions. Add the sauce on top of the noodles and enjoy your Jajangmyeon!