Set a 10-inch nonstick or well-seasoned cast-iron skillet over medium heat.

Brown the sausage: Add the smoked sausage coins to the dry skillet.

Cook the sausage, turning once or twice, until it is browned at the edges and heated through, 4 to 5 minutes.

Transfer the sausage to a plate. If the skillet has more than about 1 teaspoon fat in it, carefully pour off the extra.

Mix the scallion mayo: In a small bowl, stir together the mayonnaise and half of the scallion greens. Set the bowl aside for serving.

Put the grated potato in a clean kitchen towel or several paper towels. Squeeze over the sink until a good amount of liquid comes out.

Build the pancake mixture: Put the sliced cabbage, the squeezed potato, the scallion whites, and the remaining scallion greens in a large bowl.

Add the beaten eggs, flour, salt, and black pepper to the bowl.

Stir until the vegetables are evenly coated and the egg-and-flour mixture lightly holds everything together.

Cook the first side: Add 2 tablespoons of the oil to the skillet and let it heat for about 30 seconds.

Scrape the cabbage mixture into the skillet. Press it into an even round about 1 inch thick.

Cover the skillet with a lid or a sheet of foil. Cook until the bottom is deep golden brown and the edges on top look more set, 7 to 9 minutes.