My explanation from another discussion:
This phenomenon is called "partitive apposition" and involves measurements.
Basically, in cases where there is a measurement followed by what is being measured, as with "bord" and "hoeveelheid", there is no need for a preposition (of).
What is being measured directly follows the measurement.
More possible measurements:
- een kopje koffie (a cup of coffee)
- een fles water (a bottle of water)
- een kilogram appels (a kilogram of apples)
- een aantal landen (a number of countries)
You are using 'to have' here in a different sense. You are using it to mean 'to eat' whereas the Dutch 'hebben' here means 'to possess'. The 'possess' sense in English usually isn't expressed in the continuous tense - it just sounds awkward (unless you speak Indian English).
In addition to KaiEngle's comment, your sentence sounds really awkward in English. 'whose' is usually followed by the object in question. 'Whose pasta are you having?' would be a well-formed sentence, although it has a different meaning to the sentence being discussed here.