Cut the tempeh into 1/2-inch cubes to ensure even browning and a consistent texture throughout the dish.
In a small bowl, whisk together the tamari, rice vinegar, maple syrup, and nutritional yeast until the mixture is smooth.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the tempeh cubes to the skillet and sear for 5-6 minutes, turning occasionally until all sides are golden brown and crisp.
Toss in the broccoli florets, sliced red bell pepper, and shelled edamame to the skillet.
Add the minced garlic and grated fresh ginger, then sauté for another 4-5 minutes until the vegetables are tender-crisp and aromatic.
Pour the prepared ginger-maple sauce over the mixture and stir constantly for 1-2 minutes until the sauce thickens and coats the ingredients.
Season the stir-fry with sea salt, black pepper, and red pepper flakes before serving immediately while hot.