In a medium bowl, whisk together the marinade ingredients—lemongrass, fish sauce, brown sugar, lime juice, and garlic. Add chicken and let it marinate for 15 minutes.

In a small bowl, combine peanut butter, hoisin sauce, white vinegar, and milk. Stir until smooth, adjusting consistency with more milk if needed.

Bring a pot of water to a boil and soak vermicelli noodles for 2 minutes until soft. Drain and rinse under cold water.

Heat canola oil in a non-stick pan over medium-high heat. Add chicken and cook for about 3 minutes until caramelized and cooked through. Remove, cool, and slice.

Fill a large shallow dish with warm water and dip each rice paper sheet for 2-3 seconds to soften. Lay flat on a cutting board.

Layer fresh mint, coriander, chicken, noodles, and vegetables onto each rice paper. Assemble neatly.

Roll tightly from the bottom, tucking in sides as you go, until enclosed. Repeat with remaining sheets.

Serve the rolls on a platter with peanut sauce on the side. Cut in half for presentation if desired.