I'm sure to pick up extra bags of cranberries for the freezer in the fall so that I can make this lovely, delicious jam year-round. My kids love it on peanut butter sandwiches. Jars of this pretty ruby-colored jam also make great gifts. —Marjilee Booth, Chino Hills, California
Drain raspberries, reserving juice; add enough water to juice to measure 1-1/2 cups. Pour into a Dutch oven. Add raspberries and cranberries; stir in pectin. Bring to a full rolling boil over high heat, stirring constantly. Stir in sugar; return to a full rolling boil. Boil and stir 1 minute.
Remove from heat; skim off foam. Ladle hot mixture into six hot half-pint jars, leaving 1/4-in. headspace. Remove air bubbles and adjust headspace, if necessary, by adding hot mixture. Wipe rims. Center lids on jars; screw on bands until fingertip tight.
Place jars into canner with simmering water, ensuring that they are completely covered with water. Bring to a boil; process for 10 minutes. Remove jars and cool.