Add half of the butter to the frying pan. Toast the slices of bread, on one side, in half of the butter until crisp and golden brown.
Turn the slices of bread on the other side. Top one of the slices of bread with morbier cheese, drained sauerkraut, slices of venison meat, more cheese & spicy mustard. Then add the other slice of bread, with crispy side on the inside.
Toast the sandwich in the rest of the butter until golden brown & crispy. Add the lid to the frying pan (at the end) to make sure that the cheese melts.
When your frying pan is big enough, you can fry the egg sunny side up next to the toasted sandwich. Otherwise, fry the egg in another pan.
Serve the toasted sandwich with the egg and fresh basil leaves.