Toss peeled and sliced peaches with sugar, lemon juice, and cinnamon. Cover, refrigerate and let macerate at least for a couple of hours, preferably overnight or all day.
Puree 1 1/2 cups of the peaches (save the rest for mixing in after you make your ice cream), and then mix puree with cream, buttermilk and vanilla.
Freeze according to your ice-cream maker’s instructions.
Note: To peel the peaches, I place them into a pot of boiling water for 30 seconds, and then transfer them to a bowl filled with ice water to halt the cooking. The skin should rub right off after blanching. If you use canned, you also might want to use less sugar if they were canned in syrup.
If you're using whole peaches, the amount can vary depending on size, anywhere from 4-6. If you're concerned about wasting produce, I'd start with the smaller number and go from there.