Chop onions as evenly as you can to ensure even caramelization. Over medium heat, melt butter and cook onions, covered, on just under medium heat, stirring occasionally for about 30-45 minutes until the onions are very tender and have released a lot of water.

Take off the lid and lower to medium low heat and cook for another 30-45 minutes, stirring occasionally to encourage even caramelization. The water will start to evaporate and then the caramelization process will start. Cook until onions are a deep, caramel brown. Too light and they won't be as sweet and delicious, and too dark will be burnt. Once done, take off the heat and set aside.

In your blender, food processor, or in a pyrex cup with a stick blender (which was my method of choice), blend tofu, worcestershire sauce, salt, and black pepper.

Combine the caramelized onions and tofu mixture and serve with lightly salted plain chips. Adjust salt to taste.