4 side servings; adapted from Amanda Gold, San Francisco Chronicle, October 2011
Slice fennel and red onion very thinly, using a knife or mandoline. Reserve some of the fennel fronds for garnish. Cut apple into matchsticks.
(I slice two side planks from either side of the core so that they are easy to manage with a flat surface. Slice thinly then stack a few and slice into matchsticks. Repeat with the remaining two, smaller sides.)
Mix dressing ingredients, drizzle over slaw, and gently combine. Garnish with fennel fronds.