Drain the pineapple cans, reserving the juice. Measure out 1½ cups of juice; if you're short, add some water.
40 oz Pineapple rings
Pour the juice into a large saucepan along with half the sugar, and all of the corn syrup. Turn to medium heat, and stir until the sugar dissolves. Bring to a low boil for about 4 minutes.
3 cups Sugar, ¼ cup Light corn syrup
Turn the heat down to low, then add in the pineapple rings. Spread them out to try to keep them from touching.
Continue boiling, turning the pineapple slices frequently to ensure they're fully coated and not stuck together.
Continue cooking for 45 minutes, checking regularly to ensure that the pineapple isn't sticking, until the slices are entirely translucent.
Once translucent, remove the pineapples from the syrup and place on a cooling rack with parchment paper underneath.
Allow the pineapple to completely dry out. This can take up to overnight; if you want to dry them faster, place the wire rack in the oven with a baking tray under the rack, and bake at 200°F for about 30 minutes.
Once the pineapple is completely dry and no longer sticky, pour the remaining sugar in a shallow bowl and toss the pineapple in it to coat them completely.
Store in an airtight container at room temperature for up to 1 week, and enjoy! See more storage tips below!