Step 1

Whisk together the eggs, dashi and salt in a large bowl. Add the flour, potato starch and baking powder and whisk until just incorporated -- avoid overmixing; some lumps are okay. Add the cabbage and scallions and gently fold into the batter.

Step 2

Heat 1 tablespoon of the oil in a large skillet over medium-high heat until shimmering. Spoon in about 1/2 cup of the batter. Use a spatula to very lightly pat down the surface and to form a round about 3 inches wide and 1/2 inch high. Repeat until the skillet is full, but not overcrowded.

Step 3

Top each round with 2 pieces of pork belly, overlapping them slightly. Cook, undisturbed, until golden brown, about 3 minutes. Flip the rounds over, keeping the pork belly in place as much as possible and reducing the heat slightly if the pork belly browns too quickly, and cook until the pork belly has rendered its fat and the okonomiyaki are cooked through and golden brown, about 4 minutes more. Transfer to plates and repeat with the remaining 1 tablespoon oil, batter and pork belly, leaving behind any liquid that’s settled at the bottom of the batter. (If your pork is very fatty, you might not need to add more oil to the skillet.)

Step 4

Serve hot, pork-side-up. Drizzle with okonomi sauce and mayonnaise in zigzag lines, then sprinkle with beni shoga, aonori and/or katsuobushi (if using).

Step 5

Combine the kombu and 3 cups cold water in a medium saucepan and let sit for about 30 minutes. (You can skip this step if you’re short on time, but it does lend a little extra flavor.) Heat over medium heat until the water comes to a near boil, but doesn’t actually boil, about 5 minutes. Discard the kombu.

Step 6

Add the katsuobushi evenly over the water, bring to a boil over high heat, then immediately remove from the heat. Let steep for about 10 minutes without stirring.

Step 7

Pour the dashi through a fine-mesh strainer into a bowl or quart-size measuring cup. Do not press down on the katsuobushi, which can make the dashi cloudy and/or bitter.

Step 8

Dashi is best used the day it is made but can be cooled and refrigerated in an airtight container for up to 3 days. Makes about 2 1/2 cups