Mix noodles, vegetables, sesame, and char siu, and place in pan (the chuka soba noodles I use direct you to stir-fry the noodles after boiling them, and I stir-fry them with the onions and bean sprouts before mixing in the other veggies and meat, and putting it in the baking pan).
Mix sauce ingredients, and lace noodle mixture with sauce.
Seal with foil.
Bake at 325°F for 45 minutes.
Remove from oven and loosen foil immediately to let steam escape (so vegetables don't overcook).