Whisk all of the ingredients except for the tempeh together in a small bowl. Place the tempeh cubes in an airtight storage container and pour the marinade over them. Cover and shake the container so that the tempeh is coated on all sides. Allow the tempeh to marinate for at least two hours in the fridge, or up to a day (I usually do it overnight).
Preheat your oven to 350F. Place the tempeh cubes on a parchment lined baking sheet and give them an extra turn of black pepper. Bake the tempeh for 15-20 minutes, or until the edges of the cubes are golden brown, flipping the cubes over halfway through baking. Serve.
Leftover tempeh cubes will keep in an airtight container in the fridge for up to 4 days.