Puree the strawberries and cranberries in a food processor until the fruit is smoothly broken down. Fresh and thawed frozen berries may be handled in the same manner. Work in portions if the processor bowl is not large enough to hold all the fruit at once.

Transfer the full amount of pureed strawberry and cranberry mixture into a large saucepan.

Add the measured granulated sugar, cinnamon, allspice, ginger, and cloves to the saucepan with the fruit puree. Stir thoroughly so the sugar and spices are evenly distributed throughout the mixture.

Set the saucepan over medium-high heat and bring the jam mixture to a full rolling boil. The boil should continue bubbling vigorously across the surface even while the mixture is being stirred.

Once the mixture reaches a full rolling boil, keep it boiling for 1 complete minute.

Take the saucepan off the heat and pour in the liquid fruit pectin. Stir well to incorporate it fully into the hot fruit mixture.

Return the saucepan to the heat and bring the jam back to a full rolling boil. Boil for another 1 full minute, stirring continuously.

Remove the saucepan from the heat again. Let the bubbling subside, then skim away any foam from the surface with a spoon or ladle and discard it.

Ladle the hot jam into prepared hot jars, leaving approximately 1/4 inch of headspace at the top of each jar.

Place a clean, warm, sterilized seal onto each jar, then screw on the band until it is fingertip-tight without forcing it.

Carefully lower the filled jars into the canning pot. Make sure the jars are covered by 2 inches of water.

Bring the water to a boil, cover the canning pot, and process the jars for 10 minutes.

Remove the jars carefully from the water and place them on a heat-safe surface. Leave them undisturbed for 12 hours so the jam can cool and set.

Wipe the jars clean, label them, and store the finished jam in a cool, dark cabinet.