In a bowl, beat together the eggs, onion powder, and salt & pepper until well combined.
Heat oil in a small skillet. Add beaten eggs and let it cook lightly, about 1 minute.
On one half of the omelette, add the shredded corned beef, sauerkraut, and shredded swiss cheese, while setting some aside for topping.
Cook for 3-4 minutes.
Once the sides begin to set and the bottom is golden brown, flip the other half of the omelette over, covering the filling.
Top with remaining corned beef, sauerkraut, and swiss cheese.
Cook until the cheese is melted, 3-4 minutes, and remove from heat.
Plate the omelette and drizzle with Thousand Islands dressing.
Serve with toasted rye bread and enjoy!