Steam the cubed tempeh for 10 minutes prior to cooking to remove bitterness and improve absorption of the marinade.
Whisk together the soy sauce, rice vinegar, maple syrup, ginger, garlic, and sesame oil in a small bowl to create the sauce base.
Heat avocado oil in a large wok or heavy-bottomed skillet over medium-high heat until shimmering.
Add the steamed tempeh to the pan and sear for 6-8 minutes, rotating frequently until all surfaces are golden brown and crisp.
Incorporate the broccoli florets and sliced red bell pepper into the wok, stir-frying for 4 minutes until vegetables reach a crisp-tender state.
Add the shelled edamame and pour the sauce mixture over the ingredients, stirring constantly to coat.
Stir the cornstarch slurry into the pan and cook for 1 minute until the sauce thickens into a glossy glaze.
Remove from heat and serve immediately.