Combine onion powder, garlic powder, paprika, sea salt and coconut sugar in a small bowl.
Cut block of tempeh in half, then cut each half diagonally so you have four triangles. Place triangles flat on your cutting board and thinly slice. Try to make your slices as even as possible.
Place tempeh slices on a baking sheet and spray with cooking oil. Sprinkle half of the spice blend over the tempeh. Flip tempeh, spray with oil and sprinkle on the remaining spice blend.
Bake for 10 minutes. Flip and bake for another 7-10 minutes or until tempeh is golden brown and crisp. Be sure to watch closely in the final few minutes because the tempeh can quickly go from golden brown to burnt.
Enjoy plain as a snack or pair with your favorite dip.