Preheat your oven to 400℉. Grab your pineapple and simple syrup along with a cutting board, Chef Knife, and a large bowl. Cut the pineapple by first slicing off the ends, standing the cut pineapple upright, cutting off the skin, quartering, removing the core, and then cutting the rest of the pineapple into chunks. Lay the pineapple chunks onto the parchment lined sheet pan, and roast in the preheated oven for about 30 minutes. You want the pineapple to just lightly dry out but not take on any color (a little bit around the edges of some pieces is okay). Allow the fruit to cool, just a few minutes.
Place the roasted pineapple into the blender, along with the simple syrup, and process, 1-2 minutes until the mixture is smooth.
Pour the mixture into a container with a tight-fitting lid, or a glass bowl tightly wrapped with plastic. Place in the refrigerator for a few hours to get cold.
After chilling your sorbet mixture, add it to your ice cream maker and process, about 30 minutes. The texture will thicken once it's been churned but won't be the same consistency as ice cream.
Spoon your churned sorbet into a 1.5 to 2-Quart, freezer safe container or ice cream tub, such as this one from Tivolo. Freeze for at least 4 hours, or ideally overnight for the best consistency.