Remove a little bit of the peach peels, remove the pits, and quarter each peach. (It is important to get the additional pectin found in the skin of the peaches.)
Add the peach quarters and pineapple chunks to a food processor. lock the lid in place and puree to your desired chunkiness.
Transfer puree into a medium saucepan. Stir in the powdered pectin and bring to a boil over medium-high heat.
Once boiling, add in the sugar and stir regularly for about 1 minute. Remove the pan from the heat and stir for about 5 minutes to cool the jam.
Pour the hot jam into 8-ounce freezer-safe mason jars. Be sure to leave 1/2-inch of space at the top and then place a lid on each jar.
Let the jars sit for 24 hours on the counter. (This will seal the jars as the jam cools.) Use immediately or store in the fridge for up to 3 weeks. You can freeze the jam for up to 1 year. Thaw a jar of frozen jam in the fridge overnight before using.
Notes
This recipe makes 56 ounces of jam. You'll need fourteen 4-ounce mason jars or seven 8-ounce mason jars to store it all.
Make sure your mason jars are freshly sterilized or washed with hot water before filling.