Bring a small pot of water to a boil. Add the diced sweet potatoes and cook until fork tender, 5-7 minutes. Drain the sweet potatoes and transfer to the bowl of a food processor. Add the cannellini beans, bread crumbs, egg, Parmesan, lemon zest, salt, pepper, paprika and oregano. Pulse for 1 minute until everything is full incorporated and smooth.

Remove the sweet potato mixture from the food processor and divide it into four equal 4-ounce portions. Form each portion into a patty to fit your preferred burger bun.

Heat the olive oil in a large skillet over medium high heat. Add the sweet potato patties to the hot oil and cook until golden brown, 4-5 minutes per side. Transfer each patty to a burger bun bottom.

Cut the avocados in half lengthwise. Remove the pit from the avocado and discard. Remove the avocado from the skin and cut the avocado into thin strips. Top each sweet potato patty with one-quarter of the avocado strips. Add additional toppings as desired and top with the top half of the bun. Serve immediately.