1. What does it mean?
단짠 combines 단맛, sweetness, with 짠맛, saltiness. It describes a sweet-salty flavor pairing, or the habit of alternating a sweet bite with a savory one. 단짠단짠 repeats the rhythm.
Also written or said as danjjan
2. The nuance
It is a taste description, not a claim about a food's nutritional quality. Figuratively it may describe pleasant and difficult moments alternating, with context supplying the metaphor.
3. Examples
“치즈와 잼을 같이 먹으니 단짠 조합이네.”
Cheese with jam makes a sweet-and-salty combination.
“단짠이 좋아도 오늘은 조금만 맛볼래.”
Even though I like sweet and salty flavors, I'll just have a little today.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.