Vanilla and nutella swirl cookies

Well, first of all, sorry for the poor quality of the photo and the (more than usual) lousy presentation of the cookies -_-U
I meant to give away some of the cookies to friends (and to boyfriend) and to store the very few that were left in a cookie box but, unfortunately, my parents found them and ate them before I had time to take a more decent picture of them T_T
Indeed, this picture was taken with my mobile phone after I packed the cookies that I were going to be given away and before I remembered to store the leftovers. Well, I suppose that's good because it means that they liked them (but I liked them too and I wished I had some more T_T).

This is another recipe (yes, again) from the book Chocolate Galore (in Spanish is Chocolate a gogó). The original recipe from the book calls for 2 teaspoons of nutella, but I used 1 tablespoon in order to get more flavour. And I changed again the amount of sugar that the recipe states, using 50g instead of 75g. Also, I don't know if it's because I used more nutella thant I was told to, but I had to increase the temperature of the oven and the baking time: the original recipe says that 160º degrees Celsius and 10-12 minutes are enough, but I needed 180ºC and 15 minutes to get my cookies done.

So, the recipe is as follows:

Ingredients:        

175g butter (at room temperature)
1 large egg, beaten
1 teaspoon vanilla extract
50g confectioners sugar
1 tablespoon nutella
225g all-purpose flour
1 teaspoon cocoa powder

Method:

1. Preheat oven to 180ºC.
2. Cream butter and sugar until light and fluffy.
3. Mix in the vanilla extract until well combined. Then add the flour and work the mixture until you have an elastic dough.
4. Divide the dough into two parts and add to one of the parts the cocoa powder and the nutella. Mix until well combined.
5. Extend, with a rolling pin, each dough in a floured surface until you get two rectangles, about 15x20 cm each. If the doughs are not hard enough let them rest in the fridge for 10-15 minutes.
6. Put the nutella dough on the plain dough and press lightly. Trim the edges and fold it, just like a swiss roll.
7. Let the roll rest in the fridge for half an hour. Then cut it in slices of about 6cm each and put them well separated in the baking pan.
8. Bake in the preheated oven for 12-15 minutes until they sighly brown.
9. Take the cookies out from the oven and let them cool for 2-3 minutes in the tray before transfering them to a wire rack. You can keep them for a week in an air-tight container.