les mélanger aux dés de kaki - 'a mixture of' or 'mix with'?
I just did this translation: Concasser les noix et les mélanger aux dés de kaki, and my translation was 'crush the nuts and the mixture of diced persimmon', and while it gave me the points, the best answer was 'crush the nuts and mix with the diced persimmon'. To me the 'best answer' looks wrong, as 'les mélanger' suggests 'the mixture', not the verb 'to mix'. What does anyone else think?
"Concasser les noix et le mélange de dés de kaki". This doesn't make that much sense, unless you consider the diced persimmon a mixture (of dice?). You're right: "les" in "les mélanger" is a reference to the nuts, so it means "mix them". Note on the side: the infinitives of the verbs are used here in the role of imperatives, which is less direct than saying "concassez" (polite) or "concasse" (informal). This is typical for recipes and other types of impersonal instruction.
To answer your second question about translating the sentence: "Crush the nuts and the mixture of diced persimmon" - "une mélange" is "a mixture" in French, so you can say something like: "Concassez les noix et la mélange de kaki." Another nice thing is that "melange" is an English word that we borrow from French, so you can use it amongst high society now in place of the word "mixture." Make sure you are eating some fine Comté and drinking some red wine from La Bourgogne (Burgundy) when you are doing so, however.. ;)