Here's a quick easy recipe for Condensed Milk Biscuits from bestrecipes.com
Easy to prepare, quick to cook. Perfect.
Only four main ingredients: butter, sugar, condensed milk, SR flour. Then add chocolate bits, nuts, sultanas etc to taste.
The recipe is for 500g choc bits. I added about 100g and it was fine, I suspect you could get away with adding nothing for plain biscuits. I cooked them in slabs in trays rather than rolling biscuits (this takes too much time). The oven probably needs to be cooler when cooking this way, but I'm not sure as I have no idea how hot my oven is, except that its usually too hot as I'm always burning things.
I also wonder if you could get away with not adding the extra sugar, condensed milk is fairly sweet as it is.