Steam the tempeh: bring water to a boil then place the tempeh over top in a steamer basket. Cover with a lid and steam for 15 minutes, flipping the tempeh half way through. Remove from heat and set aside to cool.
Cut the tempeh: Once the tempeh is cool enough to handle, cut it into triangles. Slice the block in half lengthwise then cut into triangles. You should have about 16 pieces.
Make the marinade: in a large bowl, combine the avocado oil, broth, vinegar, seasoning, garlic, and salt & pepper. Stir to combine, Add the tempeh to the bowl then use a spoon to toss until the pieces are evenly coated. Cover the bowl with a towel or wrap, then allow to marinate for a minimum of 1 hour or up to overnight in the refrigerator.
Cook the tempeh: Preheat the oven to 375°F then line a baking sheet with parchment paper or a silicone mat. Arrange the tempeh pieces on top of the baking sheet then bake in the oven for 20 mins, flipping half way through. Serve warm and enjoy!