Place rice vermicelli in a large heatproof bowl. Pour boiling water over the noodles to cover by 1 inch and let soak 3–5 minutes until tender but not mushy. Drain well, rinse under cold water, and set aside, fluffing with fork to prevent clumps.

Prep vegetables and herbs

Peel and julienne the carrots into thin matchsticks. Halve, seed and cut the cucumber into thin matchsticks. Core and thinly slice the red bell pepper. Thinly shred the Napa cabbage. Trim and thinly slice the green onions on a bias. Roughly chop cilantro stems and reserve leaves. Slice avocado into thin slices if using. Pick and wash basil and mint leaves; pat dry.

Lightly soften cabbage (optional)

If the Napa cabbage is very firm, heat 1 tbs neutral oil in a skillet over medium heat, add shredded cabbage and a pinch (about 1/4 tsp) salt, sauté 1–2 minutes until just wilted, then remove from heat and cool. This step is optional and recommended if you prefer a softer interior.

Season fillings

In a bowl combine drained vermicelli, sautéed or raw cabbage, carrots, cucumber, bell pepper, green onions, chopped cilantro stems, 1 tsp sesame oil, 1/2 tsp salt and 1/2 tsp white pepper. Toss gently to combine. Taste and adjust seasoning; the filling should be lightly seasoned since dipping sauce provides most flavor.

Soften rice papers

Fill a shallow large pan or pie dish with warm water (not boiling). Working one at a time, submerge one rice paper for 6–10 seconds until it becomes pliable but still slightly firm — it will continue to soften on the work surface. Lay softened wrapper on a clean damp tea towel or cutting board.

Assemble rolls

Place about 1/12th of the filling (roughly 2–3 tbs vermicelli mixture) horizontally across the lower third of the softened wrapper. Top with 1–2 basil leaves, 1–2 mint leaves, 2–3 cilantro leaves, and 2–3 avocado slices if using. Fold the bottom edge up over the filling, fold in both sides snugly, then roll tightly away from you to close, making a compact cylinder. Repeat with remaining wrappers and filling. Keep finished rolls covered with a damp towel to prevent drying.

Slice and plate

If desired, cut each roll in half on the bias with a sharp damp knife for nicer presentation. Arrange rolls on a bed of shredded lettuce or microgreens and garnish lightly with toasted sesame seeds and a lime wedge.

Sweet Chili Dipping Sauce

In a small bowl whisk together sweet chili sauce, rice vinegar, soy sauce, lime juice, grated ginger and minced garlic until smooth. Taste and add 1 tbs water if too thick. Add chili flakes to increase heat if desired. Adjust acidity or salt to taste. Chill until ready to serve.

Transfer sauce to a small serving bowl and sprinkle with a few toasted sesame seeds for garnish.

Serve

Serve 2 spring rolls (halved) per person as an appetizer with the sweet chili dipping sauce on the side and lime wedges. Provide extra herbs and microgreens for diners to add inside or alongside.