In a large saucepan, combine the peach puree, light brown sugar, lemon juice, and cinnamon. Make sure your saucepan is big enough to handle the mixture bubbling up—this will double in volume during boiling.
4 cups peach puree, 2 cups Light Brown sugar , 1 Tablespoons Lemon Juice , 2 teaspoons cinnamon
Bring everything to a roiling boil, then reduce the heat to medium-low and simmer.
Stir well from the bottom every 3–4 minutes with a spatula. You don’t want it to scorch!
After about 45 minutes, the mixture should be thickened to a rich, spreadable consistency. Keep in mind it will thicken more as it cools .
Fill sterilized jars with hot peach butter, leaving ¼ inch headspace.
Wipe rims, add lids finger-tight, and process in a boiling water bath for 10 minutes, making sure jars are covered by at least 1 inch of water.
Remove jars and let sit upright for 24 hours. Listen for the ping—that’s the sweet sound of a proper seal!