Start the black thread on the dry fly hook and catch it in down to the start of the bend.
Pull a small clump of Opossum dubbing (guard hairs are fine), lick your fingers rather than waxing, and dub a thick but short noodle; wrap it forward, tightening as dubbing lays down, with a little taper if you like. Stop well short of the eye: two components still go on up front.
Cut a decent, not huge, bunch of Orange deer hair; pull the underfur out and stack it if you like (either way works).
Keep the thread flat rather than corded so the hollow hair does not flare too much. Hold the bunch straight above the shank at the front of the body, lean it slightly toward you so the first wrap rolls the hair onto the top, and take several wraps without letting go.
Before releasing the butts, reach in and trim them as close as you can, then bury the stubs with thread wraps to give a smooth area for the hackle.
Select a Grizzly hackle with barbs one and a half to two times the hook gap, catch it in right in front of the wing with a couple of wraps, wrap it forward as thick as you like (Matt goes fairly thick), snip the stem.
Pull the fibers back just enough to flatten the head area, whip finish, snip or singe any trapped forward fibers, and add a drop of head cement.