Peel the casing off the sucuk. Score it lengthways with the tip of a knife and it lifts away in one piece.
Cut the sucuk into slices about ½ cm, or ¼ inch, thick. Thinner slices dry out and curl, thicker ones brown outside before the middle warms through.
Lay the slices in a single layer in a cold sahan or heavy skillet, then set it over medium heat. Starting cold gives the fat time to run out before the outside colors. Add the butter only if your sucuk is lean.
Cook for about a minute on each side, until the edges lift and there is a shallow layer of red fat in the pan. If the slices are dry, put the lid on for that first minute.
If the pan has flooded with fat, lift the slices onto kitchen paper for a moment and pour off all but a thin film, then return them to the pan.
Spread the slices out to leave gaps between them and turn the heat down to low.
Crack the eggs straight into the gaps. Spoon a little of the hot sucuk fat over the whites as they set.
Cook for 2 to 3 minutes for runny yolks, with the lid off so the yolks stay bright and clear. Cover the pan for the last minute only if you want the whites fully set on top.
Finish with the black pepper and chili flakes. Taste before adding any salt, because the sucuk has already seasoned everything in the pan.
Serve straight from the pan with plenty of bread for the yolks and the fat.