It's not roast chicken eggs, it's smoked eggs. Egg yolk is as oily as salted duck eggs. I can cook more than a dozen eggs, but I have never heard that roast chicken eggs are smoked eggs.

Boil the eggs for 5 minutes, take out the eggs, soak them in cold water, peel off the eggshells, spread a layer of aluminum foil paper on the wok, add two spoonfuls of sugar on it, put the eggs on the steamer, cover the lid, heat them over medium heat, and then smoke. Turn off the fire and let the eggs smoke for five to ten minutes until they are colored. This is smoked eggs. You can also develop what you call baked eggs on this basis. This can be mass produced.