One of the most underrated moves in the bun world, in my opinion, is when steamed buns are then crisped up in a little oil so they get a fried outer layer. The texture of the soft steamed bun with the crispy fried exterior is next level! These buns are both steamed and fried and they have a veggie filling that explodes with flavor. What does it for me is the Thai bird chili and fresh basil, so they're spicy and fresh and everything in between.
For the bun dough: In the bowl of a stand mixer fitted with the dough hook, combine the all-purpose flour, cake flour, sugar, yeast and salt and whisk to combine. Add the water and shortening and mix 10 minutes. Transfer to an oiled bowl and let sit until doubled in size, 1 to 2 hours.
For the filling: While the dough is rising, preheat the oven to 425 degrees F.
Spread the bok choy, scallions, garlic, chile peppers, onion, ginger and red cabbage in an even layer on a baking sheet. Drizzle over the peanut oil and season with the salt and pepper. Roast until cooked down and roasted, about 45 minutes. Transfer to a mixing bowl, add the basil, sesame oil, soy sauce and rice vinegar and toss to combine. Refrigerate the filling until you are ready to form the buns.
When the dough has doubled, transfer it to a work surface and knead for 2 to 3 minutes, dusting with flour if sticky. Divide the dough into 10 even pieces. Cover with plastic and let rest for 10 to 15 minutes.
To form the dumplings, flatten each dough piece into a 4-inch circle and fill with a heaping tablespoon of filling. Pinch the edges together to seal and twist (it will seem like too much filling, but the dough is stretchy enough to hold it). Cover with plastic wrap or a clean towel and let rest on a sheet tray for 30 minutes.
For the veggie buns: Heat the peanut oil in a large nonstick skillet over medium heat. When the oil is shimmery, add the buns seam-side down. Sear until golden on the first side, 3 to 4 minutes, then flip, add about 1 cup water (carefully because it will get a little spitty), cover immediately and let steam until puffy, 8 to 10 minutes. Remove the cover and continue to cook until the water is gone. Serve with soy sauce and black vinegar.