In a bowl, whisk together powdered sugar and tylose. Set aside.
In a separate mixing bowl with paddle attachment, start to beat shortening on low.
Add approx half of the powdered sugar mixture a little at a time, allowing sugar to incorporate after every addition.
Scrape bowl frequently.
Switch to the dough hook attachment. Scrape bowl. Slowly add the rest of the powdered sugar mixture, a little at a time.
Allow to mix on medium (2-4 on kitchen aid) for approx 3-5 minutes until all ingredients are incorporated.
Mixture shouldn't stick to your hands, however might be slightly sticky. At this point you can make the adjustments below if needed.