In a mixing bowl, whisk together soy sauce, maple syrup, liquid smoke, apple cider vinegar, tomato paste, smoked paprika, garlic powder, onion powder, and black pepper until well combined.
Add thinly sliced tempeh to the marinade, ensuring all slices are well coated.
Cover the bowl with plastic wrap or a lid and place in the refrigerator to marinate for at least 30 minutes preferably for several hours or overnight.
Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper or a silicone mat.
Remove the tempeh or tofu slices from the marinade and place them on the lined baking sheet, leaving some space between each slice.
Bake the vegan bacon in the preheated oven for 15-20 minutes, flipping the slices halfway through until they are crispy and browned to your liking.
Remove the bacon from the oven and let it cool for a few minutes before using it for your in sandwiches.