Start the thread behind the eye and take it back to about above the hook point.
Tie in eight or ten hackle fibers as a tail and snip any curly butts.
Leave the thread at the front of the tail, wax it, and spin on a little dry fly dubbing. Wrap a slim body forward, stopping short of the eye.
Cut a strip of 2mm foam about a hook gap wide. Tie it in on top with a couple of wraps, close to the eye but not on it.
Flatten the foam and fold it back over on itself into a loop, sized to float the fly but not huge. Bind it with a couple of wraps, then one wrap a little farther forward.
Snip the foam excess close and bury the last nub under thread.
Tie in the dry fly hackle immediately behind the foam loop, erring one size smaller if in doubt. Take four or five turns and tie off behind the foam.
Whip finish behind the foam with four wraps, then snip the hackle excess.