"Myslím na tvou polévku."

Translation: I am thinking about your soup.

[simeki]

Could it be: Myslím na tvoji polévku.

[ValaCZE]

Added, thanks. Next time just report it with the button.

[skywalker735]

And what happened with that soup?
o.0

[TTDan]

Would there be a grammatical difference in Czech between 'I think about your soup' which seems infinitive, and 'I am thinking about your soup' which is the present tense?

[ion1122]

"I think" is the simple present (not the infinitive).
"I am thinking" is the present progressive.

For the most part, a Czech verb can be translated using either, but pay attention to context!

[AndreaLiversage]

Is there a difference between ‘I think’ and “I am thinking”?

[ion1122]

Are you asking a question about English or about Czech? For the most part, Czech verbs can be translated using either the English simple present or the progressive (-ing) forms.

[A477]

is tvou or tvoji more common?

[VladaFu]

Both are common.