Learn Hardcore Dutch: Het fornuis in onze keuken is kapot, dus we koken op één pit. - The stove in our kitchen is broken, so we cook on one burner.

Many nouns ending in -uis are neuter, e.g. het huis, het gedruis, het fornuis.
When in doubt, check a reliable dictionary or language app that lists the article.

Why do we say in onze keuken instead of just in de keuken?

Because onze is the possessive adjective for wij (we/our).

in de keuken: “in the kitchen” (could be any kitchen)
in onze keuken: “in our kitchen” (specifically ours)

What does kapot mean, and how is it different from stuk or defect?

All three can indicate something isn’t working, but there are nuance and register differences:

kapot: everyday, informal (“broken”)
stuk: also colloquial (“out of order,” “broke down”)
defect: more formal, technical (“defective”)
Example:
• Mijn telefoon is kapot.
• Mijn telefoon is stuk.
• Mijn telefoon is defect.

Why is there no inversion after dus in “dus we koken op één pit”?

dus here is a coordinating conjunction (like en, maar, want, of), linking two main clauses. Coordinating conjunctions do not trigger subject-verb inversion.
Compare:

“Ik ben moe, dus we koken op één pit.” ✔
“Ik ben moe, daarom koken we op één pit.” (here daarom is a conjunctive adverb, so it does trigger inversion)

Why do we use we instead of wij in this sentence?

Dutch has two forms of “we”:

we: unstressed, very common in spoken and informal writing
wij: stressed, used only for emphasis or contrast
Here there’s no emphasis, so native speakers prefer we.

Why is it op één pit koken? Couldn’t you say met één pit or leave out the preposition?

The verb koken plus a heat source uses the preposition op in Dutch:

koken op gas
koken op een pit
Saying koken met één pit is possible but less usual. Omitting the preposition would be ungrammatical: you need op.

Why is één written with an accent in op één pit?

The accent distinguishes the numeral één (“one, exactly one”) from the indefinite article een (“a/an”). Use the accent when you want to stress that it’s exactly one:

We koken op één pit = we cook on exactly one burner
If you wrote een pit, it might read as “a burner” without the emphasis on “just one.”

What exactly is a pit on a stove? Are there other words for it?

A pit is the little ring or spot on an electric or gas stove where the flame or heating element is. Other terms:

brander (more formal, especially for gas stoves)
kookplaat (the whole cooking plate, not just one burner)
In everyday speech pit is very common.