2) The mathematician solved the problem in a mind-boggling way.
Explanation:
Option 1 uses "mind-boggling" in a context where it doesn't fit the meaning of extreme complexity or astonishment. It describes the new recipe as delicious but not mind-boggling, which suggests a different level of impact.
Option 2 correctly uses "mind-boggling" to describe the mathematician's way of solving the problem, indicating an impressive or astonishing method.
Option 3 simply states that the weather was nice, without any reference to the extreme complexity or astonishment associated with "mind-boggling."