She spends the next hour and a half preparing food to cook. From 6:30 to 8:30, she cooks.
Does food to cook equal food which is to be cooked. What's the grammar? Any other examples?
This is a nonfinite relative clause. Yes, "food to cook" means "food that is to be cooked". For some discussion, see these two Wikipedia sections: Nonfinite relative clauses and To-infinitive (scroll down to the "As a relative clause" portion).
There are many examples:
This is the place to be.
I have homework to do.
It was a sight to see.