How to desire without clinging ?

I wouldn’t choose the word desire, but... let it come, let it be (and enjoy it fully), let it go. Appreciate the whole process, embrace the impermanence as a possibility. Enjoy the present without clinging to the past or craving for particular outcomes.

Was that what you were asking?

Well, here is the way I think about it.  Liking leads to craving, which leads to clinging, which leads to becoming, which leads to stress. For me, liking is a reaction to a single event, while craving is a generalised liking for all those kinds of events. Clinging is when you build that generalised liking into your goal system. Then becoming is when you give in to the urge to act and this leads to stress, either obviously or less obviously by subltly by reinforcing the clinging.

So you can enjoy this ice cream, or enjoy ice cream in general, but try not to keep thinking about having more ice-cream, or stop the car to get  ice-cream even if that it makes you late.  Which is pretty much what Polly said too.

And how is this to be achieved?  Concentration and mindfulness.

Just my 2c worth. And I really enjoy ice-cream.