In a bowl, whisk 2 tbsp sesame paste (nerigoma), 1½ tbsp yellow miso paste (awase), 1 tbsp sugar, and 1 tbsp ground sesame seeds until the ingredients are evenly distributed into a smooth thick paste.
Add a splash of ½ tsp unseasoned rice vinegar (komezu) and whisk to loosen, then add 250 ml dashi stock a little at a time and whisk vigorously between each addition.
Continue to add the dashi until it reaches your desired dipping consistency, then stir in 1 tsp toasted sesame oil. Set aside for later, store in the fridge if you want it chilled.
Cut 200 g thinly sliced pork belly into bitesize pieces and sprinkle with a pinch of salt. Julienne 1 Japanese cucumber and cut 1 tomato into wedges.
Heat a pan and add a splash of cooking oil. Once hot, add the pork belly and stir fry until cooked through and no more pink is showing. Set aside for later.
Heat a pot of water to a rolling boil and cook 200 g soba noodles according to the package instructions. Once cooked, pour through a colander to drain and rinse with fresh cold water, rubbing them gently to remove any starch. Drop the noodles into a bowl of ice water to chill and tighten them.
After a few minutes, drain the noodles hard and gently press them to remove any excess moisture.
Serve the noodles on a zaru or tray, and arrange the pork and vegetables on a communal plate. Pour the gomadare into individual dipping bowls along side a small plate of condiments like wasabi paste, finely chopped green onions and extra sesame seeds.
Serve, dip, and enjoy!
Notes
Build the sauce in this order: Mix the sesame paste, ground sesame, sugar, and miso first, then the vinegar until glossy, then the dashi a little at a time, sesame oil last. Add the liquid too fast and the paste seizes into grainy clumps.If the sauce seizes, bring it back: Grainy or split sauce is not ruined. Warm it gently and stir a little liquid back in until it turns smooth and glossy again.No nerigoma? Rebuild the roast: Chinese sesame paste is the closest swap since it is also fully roasted. With tahini, add a few drops of toasted sesame oil and a spoon of toasted ground sesame so the sauce gets its roasted aroma back.