In Ireland it’s called Máirt Inide, in the UK we call it pancake day, in the USA it’s known as fat Tuesday or Mardi Gras. Shrove Tuesday celebrates the start of the Christian festival of lent, where traditionaly you feast on pancakes with whatever you are giving up for lent which starts the next day on Ash Wednesday. You then do not eat this one ingredient again until easter, when the resurrection of Christ happens.
Good choice, thank you for your answer ☺️