For the patty: In a large bowl, mix together the corned beef hash, eggs, breadcrumbs, and scallion.
Scoop into 3 oz patties and flatten slightly. Reserve on sheet pan.
Heat oil in a large skillet over medium heat.
Cook patties 5-6 minutes per side, until golden brown. Transfer to paper towel lined plate until ready to serve.
For the burger build: Spread the Thousand Island on the bottom burger bun. Top with one corned beef hash patty, sauerkraut, sliced avocado, bacon, and a sunny side up egg, and top bun.
