She used an F hook
​--Rnd 1: make magic ring w/ 13 sc, ss into 1st sc, ch 1, DO NOT TURN
--Rnd 2: sc in same as joining, sc in next st, (sc, hdc) in next st, (hdc, dc) in next st, (dc, hdc) in next st, (hdc, sc) in next st, sc, ss into magic ring, sc, (sc, hdc) in next st, (hdc, dc) in next st, (dc, hdc) in next st, (hdc, sc) in next st, sc, ss into 1st sc, leave long tail for attaching & finish off.
--Attaching heart--center it on front side of cozy & pull tail through cozy. weave tail up & over to 1 of the dc's @ the highest point & tack down. weave tail to lowest point of v on the top & tack down. weave over to last side, find dc @ highest point & tack down. weave tail well for strength & security.