To make the sauce, mix miso paste, tahini, lemon juice, olive oil, and tamari until smooth. Set aside.
Bring a pot to a boil. Add soba noodles and cook until just done. Add bok choy and cook until noodles are completely cooked and bok choy is bright green.
Drain noodles and bok choy, then transfer to a bowl. Mix with sauce and sprinkle sesame seeds on top to garnish!
Notes
NOTE: If you are making this gluten-free, ensure that the soba noodles are pure buckwheat noodles made in a facility that doesn't process gluten, and that you use tamari or a gluten-free soy sauce.