There is a ton of misinformation out there on the interwebs and some of it applies to properly tying an egg fly. I can’t do much about any of the other stuff but I can clear up the egg mystery. Watch this.
Hook: TMC 2457 or 2488H #8-16
Thread: GSP 50
Yolk: Alternate color McFlyFoam
Start the thread behind the eye and make a thread base about half way down the shank. Wrap back up to the eye and then back to the middle of the thread base.
Separate a large clump of your primary color McFlyFoam and stack a smaller clump of the yolk color on top of it.
Tie the McFlyFoam on top of the hook with three, very tight, wraps of thread.
Turn the McFlyFoam bunch slightly and make three more tight wraps across the bunch. This thread maneuver is exactly like tying in a set of spinner wings.
Bring the thread around the shank in front of the McFlyFoam and whip finish and clip the thread.
Pull the McFlyFoam directly above the hook without twisting it, and cut it straight across with your scissors.