Traditional Jaffna mutton roll preparation: crumb coating and thin crepe sealing?

The authentic Jaffna Chinese Roll (mutton roll) demands structural pastry technique. The filling—minced bone-in mutton simmered with roasted Jaffna curry powder, boiled potatoes, leeks, and crushed fennel seeds—must be chilled completely dry; excess gravy makes the roll burst. A thin crepe (cooked on one side only) is rolled tight around the filling with folded edges sealed using a raw flour-water slurry. The rolls are dipped in beaten egg wash, rolled in coarse dried breadcrumbs (roti crumbs), and fried in 180°C oil for 3 minutes until golden brown.