In a Dutch oven, combine the peaches, raspberries and lemon juice. Stir in sugar. Bring to a full rolling boil, stirring constantly. Stir in pectin; return to a full rolling boil. Boil for 1 minute, stirring constantly.
Remove from the heat; skim off foam. Add extract. Carefully ladle hot mixture into hot sterilized pint jars, leaving 1/4-in. headspace. Wipe rims and adjust lids. Process for 5 minutes in a boiling-water canner.