Hi there,
I would do the same thing. I would have the box of sweets that you have left (assuming that it isn't equivalent to her own body weight, if so, taking out some of them to leave a small pile) and let her visually see that the pile is running down. When you give her the treats, offer her the box/bowl/container for her to help herself to one. As she gets to the last one, she will have a visual clue that that is that, as they say and there is no more left. This will also stop her thinking you are the bad guy...!
Hope this works, and I'm sure, after the last bag is consummed, a few days later, she would have forgotten that she even used to have sweets after every meal...
Good luck.