Peel the peaches: Bring a large pot of water to a boil and prepare an ice bath. With a paring knife, score a shallow "X" on the bottom of each peach so that you just pierce the skin. Carefully add peaches to the boiling water (I use tongs). Immediately cover the pot (the peaches will cause the water's temperature to drop and you want it returning to a boil ASAP) and boil the peaches for 1 minute (uncover the pot as soon as the water returns to a boil). Remove peaches from the pot and plunge them into a bowl of cold water to stop cooking. The peach skins can now be easily removed with you fingers.

Heat the peaches over high heat, stirring every 20 to 30 seconds to prevent sticking. Bring to a full rolling boil, which takes 5 to 10 minutes. The mixture will begin to bubble around the edges, then slowly build. You know you've reached a full, rolling boil when entire surface is boiling rapidly with large, fiesty bubbles that do not stop when you stir. It may look a little foamy and the bubbles will be noisier.

Once you have your rolling boil, add the sugar in all at once, then stir to dissolve. Keep the pan over high heat and stir every 15 to 20 seconds to prevent burning. Keep heating and stirring until the mixture returns to a rolling boil (this usually takes 2 to 4 minutes more, but if you're not there yet, just keep heating and stirring). Once you hit a rolling boil, set a timer for exactly 1 minute and stir the entire time. Remove from the heat and skim off the foam (when using pectin, you do not need the jam to hit 220°F the way you would if you were using only sugar). You can discard the foam or keep it for toast (yum!).

Spoon the jam into clean jars and let cool to room temperature. Cover and refrigerate. The jam will set within a few hours. Store it in the refrigerator (I find it can last a full year, though we never have it around that long). If you'd like to can the jam for room temperature storage, please refer to the USDA Canning Guidelines for techniques.