Preheat the oven to 180C / 350F

Using an electric mixer, beat the butter and sugar util light and fluffy, about 4 - 5 minutes

Add the egg and whist to combine.

Sift over the flour, bicarb, baking soda, salt and cinnamon and briefly mix. 

Add the oats and raisin and briefly mix again. Stir by hand scraping down the bowl. 

Line 2 baking sheets with non-stick baking paper and scoop out batter to the size you like. 20ml (1 heaped tablespoon measure) will make a small biscuit). Male bigger biscuits with the double that quantity if you prefer. Allow a small amount of space between each biscuit for expansion. 

Press down lightly with your hand or a spatula to flatten.

Bake the biscuits for 20 to 22 minutes, until they just start to turn brown across the top, but do not overbake.

Remove from oven and cool completely on a cooling rack.