This is the 1213th most frequent Russian word.
какое
"What" or "which" (interrogative adjective).
Used here as an interrogative pronoun, "какое" questions about a specific attribute of an object. It agrees in gender (neuter), number (singular), and case (nominative) with the noun "блюдо" (dish).
Какое у тебя любимое блюдо?
What is your favorite dish?
In this exclamatory sentence, "какое" expresses the extent or quality of the feeling (happiness), qualifying the neuter singular noun "счастье" (happiness).
Какое счастье увидеть тебя снова!
What happiness it is to see you again!
Here, "какое" appears as part of the compound pronoun "какое-то," indicating an unspecified or vague noun, agreeing in gender, number, and case with "место" (place).