Romance drama with a Younger Cold/Reserved ML and Older FL Pairing

hmm this is really a tricky request since most dramas are more with a coldish/reserved FL and a younger sweet ML.

My Love from the stars - technically he is actually older than her, since he is an alien, but he is in the body of a young guy who is her junior. It is very sweet and very funny
Secret Boutique - the main focus is revenge and not romance but there is a coldish female lead and her younger assistent that fills your wish.

Other dramas where the female lead is also the cold one would be:
Secret Love Affair
Mother of Mine
Find Yourself
Sweet Teeth
I hear your voice

• Nagatan to Aoto: Ichika no Ryourijou 
• His and Her Secrets