In a small bowl, mix all the ingredients of the marinade. Set aside.
Boil the tempeh in a small pot filled with water for about 10 minutes. Cut the tempeh into thin slices.
Add the tempeh in slices to the marinade and mix to coat well. Let stand for 30 minutes minimum.
Preheat the oven to 375 ° F (190 ° C) and cover a baking sheet with parchment paper. Put the tempeh on the baking sheet taking care to preserve the marinade. Cook the tempeh in the oven for 20 to 30 minutes until golden brown. Remove from oven and coat with the remaining marinade.
Serve with grilled peppers.