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!
Notes
Pro Tips:Cooking the Pork Belly - Ensure the pork belly is golden brown and you can see that the fat has rendered out of the pork. This fat will allow you to sauté the vegetables adding more flavor to your Jajangmyeon sauce!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. Drain the water well and pour the sauce on top immediately to enjoy! Storage - You can easily make this sauce in advance to make Jajangmyeon during the week! Save the sauce and store in an airtight container for up to 3 days in the refrigerator.