"Shrove" is the past tense of the verb "shrive" - "to obtain absolution for oneself by confessing and doing penance".
In French this is Mardi Gras - "fat Tuesday" - the feasting before Lenten fasting. A time of "carnival" [The derivation of the word "carnival" is uncertain. Possibly it originates in the Latin carne vale, meaning "to farewell meat" or even "to say goodbye to the flesh". Others posit that its origin lies in the Italian carne levare, meaning "to remove meat". The Oxford English Dictionary has that "Carnival" is derived from Latin carnem levare (removal of the meat) or carnem laxare (leaving the meat).]
In Northern Springtime, I presume that, in order to have chicks etc. one must leave the eggs with the hen to hatch. One stops eating the eggs during this time - Lent. And can start eating them To obtain absolution for (oneself) by confessing and doing penance at Easter time - the origin of Easter eggs. In the quaint manner of liturgical developments, not eating eggs during Lent means one gets rid of all the eggs before Lent! Hence, the development of Pancake Tuesday - of using up all our eggs by eating pancakes on Shrove Tuesday.