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 - Prepare all fresh vegetables including avocado, carrot, cucumber, bell pepper, spinach, scallions, and herbs. Arrange them within easy reach for assembly.
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 slices of avocado, sautéed shiitake, carrot, cucumber, bell pepper, scallions, and herbs. Fold the bottom over the filling, fold in both sides, and roll tightly to seal. Repeat with remaining ingredients to make 8 rolls.
05 - Whisk together soy sauce, rice vinegar, sesame oil, maple syrup, grated ginger, minced garlic, and water in a small bowl until smooth. Adjust consistency with additional water if needed.
06 - Serve spring rolls immediately, whole or sliced in half, with dipping sauce on the side.