Put a Mustad #2 hook in the vise and start the thread.
Tie in four hackle feathers at the bend as short back legs (two per side, tips matched, splayed outward into a spread-eagle profile); wind the thread forward over the butts to lock them and build a thread base for the foam.
Cut a strip of yellow 2mm foam, fold it, and run the hook through it to split it into two front legs; sandwich the foam over the shank with plenty of super glue, gluing top to bottom.
Trim the foam square just behind the eye, slit the underside to pass the hook eye through, and fold a bottom flap back over the top so the head is about three layers thick; glue thoroughly and clamp until set.
Trim the foam to a frog-body shape (V-cut the back) and smooth the profile.