In America, this is another word for pancake. Cowboys washed them down with bad coffee for breakfast. But in Britain, a flapjack is a chewy sweet made from oats.
You might overlook flapjack as a mundane word, but it can be a high Scrabble scorer. Hit a double letter square with the "j" and you'll score 34. Stretch it between two triple word squares and you'll end up with a sweet 356.