Begin by thoroughly mixing the minced beef, finely chopped onion, eggs, chili, salt, and pepper in a bowl until all the ingredients are well combined and the mixture appears slightly fluffy. Heat a non-stick pan or griddle over medium heat and lightly grease it with vegetable oil to prevent sticking and to add a subtle crispness. Pour the prepared mixture onto the hot pan, spreading it evenly to form a flat layer. Quickly place a halved, open-faced baguette on top of the mixture, gently pressing down with a spatula to help the bread absorb the juices and to bind the sandwich together. Allow the sandwich to grill undisturbed for about 2 minutes, letting the egg cook through and the bread beneath develop a golden crust. Carefully flip the entire sandwich over to toast the exposed side of the bread, achieving a delightful crispiness without overcooking the filling. Once both sides are perfectly grilled and aromatic, remove the sandwich from the pan. For a creamy or spicy twist, spread mayonnaise and/or sambal on the sandwich before slicing. Cut the baguette into small, manageable portions and serve hot for the best taste and texture. Tip: For extra flavor, consider adding fresh herbs like cilantro or a squeeze of lime for brightness just before serving.