Learn Hardcore Norwegian: Kveldens suppe er varm og deilig. - Tonight’s soup is hot and delicious.

kveldens is the genitive form of kveld (evening). You add -s to show possession or association, so kveldens literally means the evening’s or this evening’s.

Why is there no article (en/ei/et or den/det/de) before suppe?

When you use a genitive like kveldens, that already makes the noun definite/specific. In Norwegian you don’t stack a genitive with an additional article. So kveldens suppe = the soup of the evening without any extra en or den.

Why aren’t the adjectives varm and deilig inflected with -e or -t?

They’re used predicatively (after the verb er). Predicative adjectives in Norwegian stay in their base form, regardless of gender or number. Only attributive adjectives (before a noun) get endings.

How would you use these adjectives attributively with suppe?

suppe is a common-gender noun. In the singular indefinite form, attributive adjectives take no ending:
• en varm suppe (a hot soup)
• en deilig suppe (a delicious soup)
For the definite form you add -e:
• den varme suppen
• den deilige suppen

Is the word order Kveldens suppe er varm og deilig the same as in English?

Yes. Norwegian uses Subject–Verb–Predicate here exactly like English:
Subject: Kveldens suppe
Verb: er
Predicate: varm og deilig

What’s the difference between i kveld and kveldens? Could you say i kveld suppe er varm og deilig?

i kveld means tonight as an adverb (in the evening). It cannot function as a possessive modifier for suppe. If you want to talk about what happens tonight, you’d say:
I kveld er suppen varm og deilig.
But to say “this evening’s soup,” you use kveldens suppe.

Could you omit og and write Kveldens suppe er varm, deilig?

Yes, it’s grammatically possible, but in everyday Norwegian it’s more common to link coordinate adjectives with og. Using just a comma feels more formal or literary.