Learn Dutch: Het is vervelend als jij mij steeds onderbreekt. - It is annoying when you constantly interrupt me.

The word als (when/if) introduces a subordinate clause. In Dutch subordinate clauses, the conjugated verb is pushed to the end of the clause. This is a very strict rule for word order that applies here.

Wait, isn't onderbreken a separable verb? Why isn't it split up?

Onderbreken (to interrupt) is actually an inseparable verb. You can tell by the pronunciation: the stress falls on the verb part (onderBRÉKEN), not the prefix. Because it is inseparable, it stays as one word and doesn't get pulled apart.

The English translation says 'constantly', but doesn't steeds mean 'still'?

If you see the phrase nog steeds, that translates to 'still'. However, steeds on its own means 'constantly', 'continually', or 'all the time'. It emphasizes that the action happens repeatedly.

Is it normal to have two pronouns (jij mij) sitting right next to each other?

Yes, it is very common! In a subordinate clause, the subject (jij) usually comes immediately after the connecting word (als). Since the verb is pushed to the end, the object pronoun (mij) simply follows the subject.