How to explain the curiously British entity that is the hobnob? Well, we could get into the entire "cookie vs. biscuit vs. digestive" argument but that would take far too long and involve way too many footnotes. Needless to say, the "hobnob" is a type of British cookie that is a bit firmer to the touch and has substantially more bite than traditional American cookies. I would on one hand be tempted to call them oatmealy (as there is a significant amount of oatmeal in them) but that wouldn't capture the essence of the hobnob.
And prior to the discovery of this recipe, the hobnob was also something I thought you could only find in the store. Like Oreos. No one actually made hobnobs. And there again, I was wrong. My roommate showed me this recipe, courteously passed on to her through the wonder that is online recipe swapping. The original website for it is here, delightfully fun and maintained by people who appear to be serious advocates of tea parties. And there's absolutely nothing wrong with that.
Now I have to apologize for my frequent (and seemingly random) switches between American and British measurement styles. Believe me, I share your frustrations in determining what half a stick of American butter means in the metric system. I can only say that I work on both systems, employing both scales and cups at the same time. I do know that there is a wonderfully handy conversion chart at the back of the latest edition of the Joy of Cooking which has saved me time and time again. And, knowing the internet, there's probably some wonderful online conversion chart where you can find out any measurement in terms of any other. If you do know of it, please share the wealth!
Ingredients
225g self raising flour
225g sugar
225g porridge oats
225g margarine/butter
1tbsp golden syrup
1tbsp hot water
1/2 tsp bicarbonate of soda
Method 
Mix the flour, oats and sugar in a bowl
Add any extra ingredients such as raisins/chocolate chips if you want
In a pan, melt the margarine, syrup and water
Once melted, stir in the bicarbonate of soda and then add to the dry mix
Mix well, then make smallish balls (the recipe makes 35 – 50 depending on size), place on a greased tray and flatten slightly
Bake at 180°c for 15 minutes until golden, then cool for a few minutes on the tray before moving to a rack.
Spread a layer of chocolate on the top (if you’re making chocolate ones)