If you are looking for something very sweet you should visit choco museo. You will find this quite unique place in Cusco, Ollantaytambo, Pisac as well as in Lima.
If you are not a big fan of sweets, anyway it can be a good idea to jump there up for a while, because they have interesting museum about cacao and some lessons how to prepare delicious products from it.
This place is also perfect for those who are looking for unique, sweet gift from the travel. Among others you can buy here liqueurs, chocolates, marmeladas and a lot of other delicious products.
Here you can check their website.