1/2 cup low-sodium soy sauce (tamari for gluten-free)
1/2 cup water
1/4 cup brown sugar
2 tablespoons rice vinegar
1 tablespoon sesame oil
3 cloves garlic, minced
1/2 teaspoon ground ginger
2 tablespoons corn starch
1/4 cup cold water
For serving: cooked brown rice, sesame seeds, green onions
Preheat oven to 375ºF. Lightly grease a baking sheet.
Cut the tempeh into 1/2-inch cubes and place on the baking sheet. Add broccoli, bell pepper, and zucchini to the baking sheet.
In a medium saucepan, add soy sauce, water, sugar, rice vinegar, sesame oil, garlic, and ginger; whisk to combine. Bring to a boil, then reduce heat to low. Simmer for 5 minutes.
To a small bowl, add cornstarch and cold water. Whisk until smooth, making sure there are no lumps. Pour cornstarch slurry into the pot; whisk to combine. Simmer for 5 minutes, until sauce has thickened. Remove from heat.
Pour teriyaki sauce over tempeh and vegetables. Toss to evenly coat.