Actually, Fernando...
The concept of peanut butter is really no different than nocilla. What it that? Cream of hazelnuts mixed with chocolate?
I love both nocilla (or Nutella) and Peanut butter. The only thing that I put on my peanut butter sandwiches are either grape jelly (Welch´s if at all possible) OR bananas, but never both at the same time. Peanut butter is also great smeared on apple slices!! And on marshmallows. Yes, I am very golosa!!
Chris R, for starters, there is a great Chinese food store underneath the Plaza de España. Take the pedestrian entrance to the underground parking and you will find a number of shops... one of them being the Chinese food store. I was so excited to find bok choy and chinese sausage there, not to mention patis (Filipino fish sauce).
I have also discovered 3 additional Chinese grocery stores in the Tetuán district. I think the street name is Calle General Margallo... or something like that. The metro stop is Tetuán. I will try to find the exact address and post it here for you.
Is there a specific kind of Asian food that you are looking for? The ones on General Margallo carry a fairly ample selection of vietnamese as Filipino food products along with the Chinese products (including Chinese beer).