Scrub and pat dry the potatoes, then pierce them with a fork. Place the potatoes on a baking sheet. Season with salt. Bake for about 1 hour, until the potatoes are cooked through (test with a skewer).
Let the potatoes cool, then cut them half (lengthwise). Using a spoon, scoop out the potato flesh, making sure the skin doesn’t tear.
Place the potato skins, skin side down, on an oiled baking sheet. Bake for another 8-10 minutes until crispy and golden.
Finely chop the frankfurters and the pepper/sundried tomatoes. Mix these with the potato flesh, using a fork. Fold in the cheese, season with salt & pepper.
When the potato skins are crispy, stuff them with mixture. Scatter some grated cheese on top.
Bake for another 10 minutes or so until golden brown.
Serve warm with a mixed salad on the side.