Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Cut the tempeh into 1-inch cubes and halve the Brussels sprouts, ensuring they are uniform for even cooking.
In a small bowl, whisk together the tamari, maple syrup, olive oil, and garlic powder until well combined.
Place the tempeh cubes, Brussels sprouts, sliced red bell pepper, and edamame into a large mixing bowl.
Pour the maple-tamari glaze over the ingredients and toss thoroughly until every piece is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet, leaving space between pieces to allow for roasting rather than steaming.
Season the tray with sea salt and black pepper.
Roast for 22-25 minutes, tossing halfway through the cooking time, until the tempeh is deeply browned and the vegetables are tender and caramelized.