Mince the onion and peel and slice the avocado into bite-sized pieces.

Heat butter in a pan over medium heat. Once melted, add minced onion and sauté for about 2 minutes until softened. Sprinkle flour and cook for another 2 minutes until incorporated.

Add cold milk to the pan and stir until the mixture thickens. Add crab meat, salt, and pepper, then mix well. Transfer to a heatproof container and let cool.

Dip rice paper in lukewarm water to soften. Place 1/6 of the crab mixture and avocado on each sheet. Fold the sides inward and roll tightly. Repeat for all 6 rolls.

Coat each roll in flour, beaten egg, and breadcrumbs in sequence.