Why did my cookies come out like this?
It can be challenging to get recipes exactly right in different parts of the world, but not to worry - you can usually fix it with some modifications. This may require some trial and error. 

There are a few things which could be going wrong:


too much liquid: this is a US recipe, and US large eggs are generally smaller than the rest of the world's large eggs, so you could be adding too much egg. You could also be adding too much butter - a stick is 1/2 US cup of butter by volume or 113 grams. Try weighing the butter to get the right amount. The recipe also calls for bread flour, which has a high gluten content, and gluten soaks up liquid. If you aren't using bread flour then there could be too much liquid. In any case the answer is use less butter and/or egg, or increase your flour content a bit
The dough is too warm: warm dough will spread out much faster, try sticking it in the refrigerator for an hour or so, and return the dough to the fridge while your cookies bake
The dough hasn't rested: most cookie doughs need some time to meld after mixing, to allow the ingredients to completely combine. Try letting it rest. Steps 2 and 3 are both accomplished by wrapping the dough and putting it in the fridge
Too cool an oven: Cookies stop spreading and rise when the mixture crystallizes and gains some rigidity. If the oven is too cool then the dough has more chance to spread before it crystallizes. If you can find one buy an oven thermometer, that will tell you whether your oven is the right heat. You could also try moving your cookies higher in the oven


What is isn't likely to be is too much baking powder or baking soda. Your spread comes from other factors.