Ultimately, I adapted a recipe from recipe.com for the version I ended up going with. We only had about 4 pounds of apples and pears, so I had to modify it.
Apple-Pear Butter2 pounds pears
2 pounds apples
2 cups apple juice
1 cup dark brown sugar
½ Tbsp ground cinnamon
1 tsp ground ginger
¼ tsp ground nutmeg
¼ tsp ground cloves
juice & zest from one lemon
powder deuce for the ground spices.)
I peeled and sliced the fruit with the food processor, added the rest of the ingredients, then cooked it on the stovetop for about half an hour.
I let it simmer for about 45 minutes or so over low heat, stirring occasionally, until it was good and thick. Then I transferred the apple pear butter into jars. It cooked down to just over 2 pints, so I didn't bother to cook it in a hot water bath. I'll just pop the jars into the refrigerator.