I love the inclusion of an exclamation point. Because who wouldn't be excited about having cookies? :)
One small note - it is singular for ciasteczko. And both this words are diminutive form of 'ciastko' (plural 'ciastka')
...which may look as another diminutive form of the word 'ciasto', and etymologically very likely is, but means 'cake' or 'dough', so let's not dig any further ;)
Ciasteczka is also a diminutive, usual form plural from ciastko are ciastka :)
Tistechko - in Ukranian it means a little cake. It's really easy for us to lern Polish)
Why isn't "cookie" acceptable instead of "cookies"? My answer "I've got a cookie" wasn't accepted.
Ciasteczka is plural except when in the Genitive case, and here it isn't genitive.
if the word is singular it would remain singular The plural of the word is translated as plural