01 - Bring a medium pot of water to a rolling boil. Gently lower the eggs into the water and boil for 9 to 10 minutes until hard-boiled. Transfer immediately to an ice bath to cool completely, then peel and chop into medium dice.
02 - In a medium bowl, mash the ripe avocado until mostly smooth with small chunks remaining. Add the mayonnaise, Dijon mustard, and lemon juice. Stir vigorously until completely combined and creamy.
03 - Gently fold the chopped eggs and chives into the avocado mixture. Season generously with salt and black pepper to taste. Mix carefully to avoid over-mashing the eggs.
04 - Lay each collard leaf flat on a cutting board. Using a sharp knife, trim the thickest part of the center stem to create a more pliable wrapper. Blanch the leaves in boiling water for 30 seconds to soften, then immediately plunge into ice water. Pat thoroughly dry with paper towels.
05 - Place a prepared collard leaf on a flat work surface. Spoon approximately one-quarter of the egg salad mixture onto the center of each leaf, spreading slightly. Layer with julienned carrot, cucumber, bell pepper slices, and sprouts if using.
06 - Fold in both sides of the collard leaf toward the center, then roll tightly from bottom to top in burrito-style fashion. Slice each wrap in half diagonally for easier handling. Serve immediately or wrap tightly in parchment paper and refrigerate for up to 24 hours.