I don't know about the flap jacks but I make christmas pudding muffins, they are very yummy and very easy.
9oz Plain Flour
4 tea spoons baking powder
1/2 tea spoon salt
a few tea spoons mixed spice (not an exact science this, I can never remember how many and it always turns out great)
8fl oz milk
3fl oz fat (corn oil, veggie oil, metled butter or marge) - I use corn oil
1/2 jar of mincemeat, usually whatever is on offer at the time!
1/2 pot of glace cherries - chopped into little bits.
Very important keep wet and dry stuff apart until the very last minute.
Put oven onto heat at 200 ish - fairly hot
Mix all the dry stuff together
Mix all wet stuff together (but keep away from the dry)
Put paper cases in muffin tin - this mixture makes 12 big muffins.
When the oven is hot and you are ready to cook the muffins, add the wet stuff to the dry stuff, mix for 30 seconds, until everything is just about combined then put into the paper cases and into the oven.
After 20 - 25 mins check they are cooked.
It is important to keep wet and dry ingredience apart until the last moment as the baking powder starts to raise and you want this to happen in the oven not in the bowl.
When cool sprinkle with icing sugar to make them look extra festive.