01 - Heat a non-stick skillet over medium heat. Add sliced shiitake mushrooms and sauté for 5-6 minutes, stirring occasionally, until tender. Set aside to cool.
02 - Slice avocado, julienne carrot and cucumber, thinly slice bell pepper, and arrange spinach, scallions, cilantro, and mint within easy reach.
03 - Fill a shallow dish with warm water. Dip one rice paper sheet in the water for 10-15 seconds until just softened, then carefully lay flat on a clean kitchen towel or cutting board.
04 - Place a small handful of spinach or lettuce in the center of the rice paper. Top with avocado slices, sautéed shiitake mushrooms, carrot, cucumber, bell pepper, scallions, and fresh herbs.
05 - Fold the bottom of the rice paper over the filling, then fold in both sides and roll up tightly to secure. Repeat with remaining ingredients to make 8 rolls total.
06 - Whisk together soy sauce, rice vinegar, sesame oil, maple syrup, grated ginger, minced garlic, and 1 tablespoon water in a small bowl until smooth. Adjust consistency with additional water if desired.
07 - Serve spring rolls immediately, whole or sliced in half, with dipping sauce on the side.