When serious-minded person is put into non-serious situations, or non-serious/comical character being depicted as serious.
Like the trope of the same name, these pictures present someone or something of incredible badass, coolness, or charisma, but all of that is made kind of funny by a cute or silly action or object. Despite this, they maintain a completely unamused look on their faces.
Don't get this confused with "Badass Adorable" where the character is drawn looking awesome in a cute form. However, they can possibly overlap.
Put it simply:
'Baby Batman' - Badass Adorable
'Batman & Baby' - The Comically Serious