Shred the cabbage finely, julienne or shred the carrot, slice the mushrooms thinly, trim bean sprouts, and thinly slice the green onions. Mince the garlic and ginger. Measure out soy sauce, sesame oil, salt and pepper.

Sauté filling

Heat 1 tablespoon vegetable oil in a large skillet or wok over medium-high heat. Add minced garlic and ginger and sauté 15–20 seconds until fragrant. Add mushrooms and cook 1–2 minutes until they begin to soften. Add shredded cabbage and carrots and stir-fry 2–3 minutes until vegetables soften but still retain bite. Stir in bean sprouts and green onions and cook 30–45 seconds. Add 1 tablespoon soy sauce, 1/2 teaspoon sesame oil, 1/4 teaspoon salt and 1/8 teaspoon black pepper. Toss thoroughly and cook an additional 30 seconds. Remove from heat and spread filling on a baking sheet or plate to cool for 8–10 minutes until near room temperature (this prevents wrappers from becoming soggy).

Prepare Wrappers & Slurry

Make the cornstarch slurry by whisking 1 tablespoon cornstarch with 2 tablespoons water until smooth. Keep spring roll wrappers covered with a damp towel to prevent drying.

Assemble Spring Rolls

Assemble

Work with one wrapper at a time on a clean flat surface with a corner pointing toward you (diamond orientation). Place about 2–3 tablespoons of the cooled vegetable filling horizontally across the lower third of the wrapper, leaving ~1 inch of space at the edges. Fold the bottom corner up over the filling, tuck tightly, then fold both side corners toward the center. Brush the top corner edge with a thin line of cornstarch slurry and roll up to seal. Repeat with remaining wrappers and filling. You should get about 6 spring rolls.

Fry Spring Rolls

Heat oil

Pour 3–4 cups neutral oil into a deep skillet or pot to a depth of about 1 to 1.5 inches. Heat over medium-high to 350°F (175°C). If you don't have a thermometer, test by dropping a small piece of wrapper— it should sizzle and rise to the surface.

Fry

Fry 2–3 spring rolls at a time, seam side down, for 2.5–3.5 minutes turning occasionally for even browning. Fry until golden brown and crisp. Avoid overcrowding to maintain oil temperature.

Drain

Using a slotted spoon or tongs, transfer fried spring rolls to a paper-towel-lined plate to drain excess oil. Let rest 1–2 minutes before serving so filling sets slightly.

Serve

Slice spring rolls diagonally if desired, garnish with chopped cilantro or parsley, and serve hot with sweet chili sauce, soy-vinegar dipping sauce, and lime wedges on the side.