Wrap tofu in paper towels and gently squeeze to remove any excess moisture. Cut tofu into 2-inch cubes. Place cubed tofu into a large mixing bowl.
Sprinkle cornstarch over the tofu and toss to coat.
Combine remaining ingredients in an immersion blender. Blend until completely mixed together.
Pour mixture over the tofu in the bowl and toss to coat. Allow to marinate for 30 minutes.
Spray baking sheet with non-stick cooking spray. Remove tofu from marinade, setting aside the excess marinade for later. Spread the tofu out onto the baking sheet. Bake in oven for 25-30 minutes, turning once halfway through.
Place saucepan of remaining sauce over medium-high heat. Bring to a boil then turn heat down to medium. Make a cornstarch slurry by whisking together cornstarch and water and drizzling it into the saucepan. Stir or whisk occasionally until thickened.
Remove tofu from oven and brush with thickened sauce.