Coarsely chop the strawberries and cranberries in a food processor or grinder (do not puree). It’s fine if you still have some larger chunks of fruit – you can mash them with a potato masher or a wooden spoon while they’re cooking. You don’t want the fruit totally pureed, because this is jam (not syrup or jelly!) – and it should have some chunky pieces of fruit throughout.
Transfer the fruit to a large Dutch oven. Add orange zest, cinnamon, cloves, allspice and sugar.
Bring the mixture to a full rolling boil, stirring occasionally. Once the mixture comes to a full rolling boil, continue the boil for exactly 1 minute.
Remove from the heat; stir in pectin and return to a full rolling boil. Once the mixture returns to a full rolling boil, set a timer and boil for exactly 1 minute, stirring constantly. Remove from the heat.
Cool for 5 minutes; skim off the foam. At this point, the mixture will still be quite thin – it will not look like a thick jam. That’s fine! It will thicken and set as it cools.
Carefully ladle the hot mixture into hot, sterilized half-pint jars, leaving ¼-inch of headspace. Wipe the rims clean with a damp cloth; secure the lids. Process in a water bath for 10 minutes.
Carefully remove the jars to a towel on the counter. Let stand, undisturbed, for 12 hours at room temperature. Check the seals after 12 hours by pressing the center of the lids. If the lid gives or the center button remains popped up, store in the refrigerator for up to 1 month. Properly sealed jars will keep in a cool, dark place for up to 8 months. Refrigerate after opening.