Prep the veggies: Shred the cabbage, julienne the carrots, slice the pepper and scallions, and chop the mushrooms if using. Keep the pieces thin so they cook fast and roll neatly.

Sauté the filling: Heat 1 tablespoon oil in a large skillet over medium-high. Add garlic and ginger, cook 30 seconds until fragrant. Add mushrooms (if using) and cook 2–3 minutes. Stir in cabbage, carrots, and bell pepper; cook 3–5 minutes until just tender but still bright.

Season and cool: Add soy sauce, rice vinegar, and sesame oil. Toss to coat. If the mixture looks wet, sprinkle in cornstarch and cook 30–60 seconds. Spread the filling on a plate to cool slightly. Cool filling prevents soggy wrappers.

Preheat the air fryer: Set to 375°F (190°C) for 3–4 minutes. Lightly oil the basket or use a perforated liner to reduce sticking.

Assemble the rolls: Place a wrapper on a clean surface like a diamond. Spoon 2–3 tablespoons of filling near the bottom corner. Fold the bottom corner over the filling, then fold in the two sides snugly. Roll up tightly toward the top corner. Brush the top corner with the flour-water slurry and seal. Repeat with remaining wrappers.

Light oil for crispness: Brush or spray each roll lightly with oil. This step helps the wrappers blister and crisp evenly.

Air fry: Arrange rolls in the basket in a single layer with space between them. Cook at 375°F (190°C) for 7–9 minutes. Flip and cook another 4–6 minutes until deep golden and crisp. Time may vary by air fryer; keep an eye on them in the last few minutes.

Serve: Let rest 2 minutes to set. Serve hot with your favorite dipping sauce.