The Forbidden Flower

Both of these dramas are including the same male lead who is showing the same affection and performance.
It is based on the opposite concept for the male lead of being the younger in the old drama and the old in the newest one.
But though it is been 21 years difference between the both, where they embody the same characters of male lead in my opinion with same romantic genre story.
What is the common I think is that the relationship between the leads is not lasting for long time at the end of story and painstinkly resisting to not be separated.

In only one term these two dramas are alike, that of temptation. Love and physical attraction. It is interesting to see how far the fire of desire will take them.

If you like The First Frost vibe (slow and deep) then you have to watch The Forbidden Flower. Also similar to have some kinda trauma and etc. (YOU HAVE TO WATCH IT)

Similarities:
-Both have leads with a terminal illness.
-Both have leads going through struggles because of that and coming to terms with it.
-Both sets realize that only by being truly together with support can they live each day to the fullest, regardless how short that time is.
-Both are melodramas.

They are equally sexy. You will get butterflies in your stomach watching both. Both female leads to show interest towards the male lead before the actual relationship, instead of acting like they are being forced.

In TFF there's a part with an office romance (in both dramas the CEO is deemed "cold" by others, and fall in love with a disliked coworker); in both dramas the male lead is a good person that cares about his cherished people, prioritising them over a career.

Jerry Yan is the male lead. He has passionate chemistry with the female lead. There are many, many misunderstandings however. It’s a sad drama, but has a happy ending. Jerry Yan is excellent. Very handsome and charismatic. His character is a cold CEO.

Protas decididas , química intensa entre os protas e trilha sonora maravilhosas.
Filmografia boa também

Although very different in the portrayal of romance I find these two dramas carry a similar vibe in terms of ML/FL connection as well as story telling.

The older ML that is somewhat a loner who isn’t an open book, brightens by the presence of the much younger FL that is filled with a youthful, optimistic desire for life.

In "My Treasure“ the relationship is that of close mentor/mentee and ultimately romance with many glances and little things to pick up on, whereas "The Forbidden Flower" is a sensual, sometimes steamy and almost poetic love story.

In both Dramas the mother/daughter relationship is also important, although it takes a more prominent place in My Treasure.

Adiantum Blue is about a pianist with a terminal illness, who wishes to spend her last happy days with her lover in Nice

In both dramas, one of the main characters gets terminally ill. And they wish to be loved by someone before they die. and they chased that person.

Older male /young female , more kissing scenes female takes initiative first and same female lead , cute scenes, quiet male lead

Chizuru, a typical Japanese young female office worker, is socially clumsy, poor at romance and unhappy with her job. Being weary from a busy and stressful city life, she seriously desires to end her life somewhere faraway from the city and leaves for deep in the mountains, where she finds one lonely house. Then she attempts to commit suicide by taking sleeping pills in the guest house but she fails... This is the beginning of her new life.

Esta es sobre un profesor que le termina gustando su alumna diferencia de 12 años aproximadamente. Lo mismo sucederia con mi pequeña boda otra pelicula sobre una relacion profesor -alumno,

there's no age gap in IOTNBO but in both dramas:
- the FL is rich (and has a great wardrobe) + has been sheltered (personalities differ though)
- FL pursues ML first and relentlessly chases after him
- has a ML who has things holding him back from starting a relationship with FL (in TFF its age gap and his responsibility as an adult, in IOTNBO its his responsibilities and her personality).
- both have great chemistry between leads
other than that plot varies wildly, but I think it's a good rec to keep in mind if you run out of directly similar ones.