Cut the peppers in half lengthways and remove the "innards". Put in a baking dish.
For the filling, mix the breadcrumbs with the mustard, egg, pepper, salt and half of the feta.
Clean the spring onions and cut into thin rings, the rest of the feta into cubes.
Now work the minced meat under the breadcrumbs. This is best done with your hands, because the mixer destroys the structure of the meat and creates a sauce.
Finally, carefully fold in the spring onions and diced feta.
Fill the pepper halves with this mixture. Put some water in the baking dish and cover the whole thing. Cook for approx. 1 hour at 190 degrees lower / upper heat in the preheated oven.