To make the spring roll wrapper, place the flour and salt in the bowl of a stand mixer and use a rubber spatula to stir to combine. Add the water and ice cubes.
Now fit the mixer with whisk or paddle attachment and stir the batter until there are no lumps appear.
Cover the bowl with a tight lid and let the batter sit for 15 minutes. Alternatively, refrigerate until ready to use and thaw to room temperature before proceeding to the next step.
While waiting for the batter to rest, prepare the filling.
In a heated non-stick pan add some oil and pan-fry tofu until golden brown, then season with salt.
Push the tofu to the side of the pan and sauté kabocha for another minute, adding more oil if needed. Season with salt and toss to combine.
Add the celery, cabbage and season with white pepper, salt, and toasted sesame oil. Stir-fry the vegetables until well-combined.
Cover the pan with a lid and let the mixture cook over medium-low heat for a minute or two until the cabbage starts to wilt.
Remove the lid and toss the mixture again. Taste and season accordingly. Turn off the heat and let the mixture cool down.
Cook the spring roll wrapper. Warm a 12-inch non-stick pan, then remove from the heat.
Drizzle some oil on a clean paper towel and rub it on the pan, covering the side.
Next, stir the batter with a spatula. Take a basting brush and dip it into the batter.
Brush a thin layer of batter to cover the base of the pan including the side. Add another layer if you prefer a thicker wrapper.
Turn on the heat and cook the wrapper over medium-low heat.
Once the wrapper turns from white to slightly translucent and the side starts to detach from the pan, turn off the heat.
Lift up the wrapper from the pan and can be used immediately or store in an airtight container once cooled.
To assemble, lay a wrapper on a chopping board.
Add a tiny spoon of sauces on the wrapper, then top with a heaping spoon of filling. Sprinkle some sesame seeds on top.
Now, bring both sides of the wrapper to the middle, lift up the bottom layer and fold over the filling by tuck it tightly. Roll it into a huge spring roll.
Cut into half and serve as-is.