Place the flour in the bowl of a food processor. With the processor running, slowly drizzle in about 3/4 of the boiling water.
Process for 15 seconds. If the dough does not come together and ride around the blade, drizzle in more water a tablespoon at a time until it just comes together.
Transfer to a floured work surface and knead a few times to form a smooth ball. Transfer to a bowl, cover with a damp towel or plastic wrap, and rest 30 minutes at room temperature (or up to overnight in the fridge).
Divide the dough into four even pieces and roll each into a smooth ball. Working one at a time, roll out into an oval on a lightly floured surface.
Using a pastry brush, paint a very thin layer of butter over the top of the dough. Roll the oval up from the short end.
When you nearly reach the end, fold the edges in to seal, then finish rolling up into a sausage-shaped cylinder.
Turn the cylinder vertical and flatten gently with your hand. Repeat the roll-and-flatten once more. Continue with the remaining pancakes.
Combine all the dipping-sauce ingredients and set aside at room temperature.
Heat about 1 inch of vegetable oil in a pan over medium-high heat until shimmering. Carefully slip in a pancake and cook, shaking the pan gently, until the first side is evenly golden brown, about 2 minutes.
Flip with a spatula or tongs and cook, shaking gently, until the second side is golden brown, about 2 minutes more. Transfer to a paper-towel-lined plate to drain.
Season with salt, cut into 4 wedges, and serve with the dipping sauce.
