Put the oven on 180/gas mark 4 or 160 fan oven.
Break up your chocolate and place in a heat proof bowl over a pan of simmering water - ensure that the bowl does not touch the water.
Cube the butter and place in the bowl with chocolate. Melt gently to combine. Occasionally stir and do not let the mixture overheat.
Place the caster sugar in a bowl of a KitchenAid.
Combine the eggs and vanilla extract in a small jug.
Once the chocolate/butter mixture is melted pour over the sugar and beat to combine.
Add the eggs - a little at a time and mix in between each addition.
Sift the flour into the chocolate/sugar mixture and with a large metal spoon fold in to combine.
Add the crystallised ginger and pour the mixture into the pan.
Place in the oven upon the middle shelf and cook for 20 minutes - check with a knife to see if cooked in the middle - you are looking for some moist crumbs to be on the knife. If too fudgey put back in the oven for another 5 minutes and check again.
Remove from oven and leave in tin for 5 minutes and then remove the brownies from the tin to cool on a rack.