In a medium mixing bowl, whisk the eggs until well beaten. Add the finely diced onion, ground beef, curry powder, salt, and black pepper, mixing thoroughly until the meat is fully incorporated into the egg mixture.

Heat 1 tablespoon of vegetable oil in a large non-stick skillet or flat griddle over medium heat. Swirl the oil to coat the bottom of the pan evenly.

Pour half of the beef and egg mixture into the skillet, spreading it out into a rectangle roughly the shape and size of two baguette halves. Cook for about 1 minute until the bottom just begins to set.

Quickly press two baguette halves, cut side down, directly onto the cooking egg mixture. Press down gently but firmly with a spatula so the bread absorbs some of the raw egg and adheres to the meat.

Cook for 3 to 4 minutes until the ground beef is fully cooked and the egg layer is golden brown and crispy. Carefully flip the entire sandwich over to toast the crust side of the bread for 1 minute, then transfer to a cutting board.

Repeat the process with the remaining oil, egg mixture, and bread. Drizzle the meat side of the sandwiches generously with mayonnaise and sweet chili sauce, slice into smaller finger-length portions, and serve immediately.