Learn Polish: Gotowanie razem to świetny pomysł. - Cooking together is a great idea.

When you say 'A is B' and both A and B are nouns (or noun phrases), Polish commonly uses to instead of the verb być (to be). If you wanted to use a form of być here, the second noun phrase would have to be in the Instrumental case: Gotowanie razem jest świetnym pomysłem. Using to keeps both sides in the Nominative case, which is often simpler and very natural in everyday speech.

Is gotowanie a noun or a verb here?

It acts as a noun! It is a verbal noun (similar to an English gerund ending in '-ing'), meaning 'the act of cooking.' In Polish, these are formed from verbs by adding endings like -nie or -cie. All of these verbal nouns are grammatically neuter.

This lesson is about adding -iwać or -ywać to make imperfective verbs. Why doesn't gotować have it?

The base verb gotować (to cook) is already imperfective. However, the rule from this lesson applies when you add a prefix to this root. For example, the perfective verb przygotować (to prepare) takes the -ywać suffix to become the imperfective przygotowywać (to be preparing). If you wanted to say 'preparing together,' the verbal noun would be przygotowywanie razem.

I know dobry means 'good'. How strong is świetny?