Prepare the Tofu:
Press the tofu to remove excess water. This can be done using a tofu press or by placing the tofu between paper towels and pressing with a heavy object.
Slice the tofu into ¼ inch thick pieces.
In a large bowl, mix soy sauce, lemon juice, vinegar, and black pepper.
Add the tofu slices to the marinade, ensuring each piece is well-coated.
Marinate for at least 30 minutes, or up to overnight in an airtight container for more flavor.
Heat 1 tablespoon of olive oil in a large pan over medium heat.
Add the onion rings and cook until they become soft and slightly caramelized, about 6-8 minutes.
Remove the onions from the pan and set aside.
In the same pan, add the remaining 1 tablespoon of olive oil.
Coat tofu In seasoned cornstarch. Fry the marinated tofu slices in batches, cooking each side until golden brown, about 3-4 minutes per side.
Remove tofu from the pan and set aside.
In the same pan, pour in the leftover marinade and vegan broth. Bring to a gentle boil over medium heat.
Add the cooked tofu back into the pan, ensuring each piece is coated with the sauce.
Let it simmer for about 5-7 minutes, allowing the tofu to absorb the flavors.
Add the cooked onions back to the pan with the tofu and sauce.
Mix gently to combine, allowing the onions to reheat.
Serve hot with a side of white rice, garnished with a sprinkle of fresh black pepper.