Preheat oven to 425°F. Peel and chop sweet potatoes, then place on a greased baking sheet.
Drizzle with a little olive oil and roast for 40 minutes until soft and cooked through.
Let cool and place potatoes into a bowl and roughly mash. Drain and rinse the black beans and add to the bowl with potatoes.
Add in the corn, diced red pepper, bread crumbs, garlic powder, onion powder, black pepper, paprika, coriander, salt and Lee Kum Kee Panda Brand Oyster Flavored sauce. Mix well using your hands, form into burger sized patties and set aside.
Grill the burgers for 3-5 minutes on each side until crispy, then set aside.
Place spinach on the bun, followed by the burger patty, and a few slices of red onion. Feel free to add any other toppings you desire.