Cut the tofu into slices.
Rinse the mixing bowl and add the tofu slices to it. First, add the dry spices (smoked paprika, cumin, chili and cinnamon). Mix well.
Next, add the lemon juice and liquid sweetener and combine so that every piece of tofu is coated in the marinade.
Transfer the tofu to the baking tray. You'll likely have some marinade left over, save that for later.