Make the Easy Baked Tempeh Bacon. The tempeh is baked but could also be cooked in a pan on medium heat. 

While the tempeh is marinading, start the caramelized onions by thinly slicing the onion.

Heat a large pan on medium heat with the olive oil. Add in the onions and cook until caramelized. Stir occasionally, add a splash of water to deglaze the pan when needed and turn the heat down if they start to burn. This is a slow process. Cook the onions for 45-60 minutes or until they are caramelized to your preference. 

Spread vegan butter on the outside of the bread or you can add the butter to the pan.

Assemble the sandwiches by adding the vegan cheddar cheese, caramelized onion, tempeh bacon and apple slices to the sourdough bread.

Heat a large pan on medium heat and cook the grilled cheese until the cheese is melted and the bread is toasty and golden brown. Cover the pan with a lid to help melt the cheese.

Remove the sandwich from the pan and add mixed greens if desired. Enjoy!