Preheat the oven to 425 degrees and line a baking sheet with parchment paper.
Add the mushrooms, soy sauce and corn starch to a bowl and toss to coat. Transfer to the baking sheet and place in the oven for 15 minutes. Flip the mushrooms (see notes) and place back in the oven for 5 minutes.
While the mushrooms are cooking, add all of the slaw ingredients to a bowl and toss to combine. Set aside.
Right before the mushrooms come out of the oven, add the soyaki sauce to a skillet over medium heat. Once bubbling, add the mushrooms and toss until they have absorbed all of the sauce and it has started to caramelize.
Heat the tortillas over an open flame or in a skillet. To assemble, grab a tortilla and add slaw and mushrooms. Finish the taco off with sesame seeds and green onion. Repeat with the remaining tacos and serve with lime wedges.
Video
Notes
Soyaki sauce is similar to Teriyaki sauce - it is a thinner consistency and has some extra ingredients (like sesame seeds). I get mine at Trader Joe's. If you can't find soyaki sauce, you can sub teriyaki sauce.
I used street style corn tortillas which are extra small. If you use regular corn tortillas, this will make 5 tacos.
The mushrooms might stick to the parchment paper when you go to toss them. Just scrap them up with a spatula.