Combine the sugar, flour, cinnamon, and baking powder together into a stand mixer bowl. With the whisk attachment, turn the stand mixer on medium speed and add the egg. Continue to mix and drop shortening into the mixer 1 tsp at a time. Continue to mix until the dough is crumbly, after about 1 minute.
Place half of the flour mixture into a prepared 9 x 13 baking dish.
Combine the sugar and cornstarch into a medium-sized bowl and mix well. Add the blueberries and carefully stir, coating all of the blueberries with the sugar mixture.
Add the coated blueberries to the 9 x 13 baking dish. Add the remaining flour mixture over the top of the blueberries.
Bake uncovered in the oven for 45-50 minutes until the top has turned a light golden brown.
Remove from the oven and allow to cool completely before cutting into squares and serving.
Store leftovers in an airtight container in the refrigerator for up to 3 days.
Store freshly baked blueberry crumb bars in the refrigerator for 3 days.
Store blueberry crumb bars in the freezer for 1 month in an airtight container.
*Nutritional information is a calculated guesstimate. Please note that this can change with different brands and modifications you may make to the recipe. For the most accurate information, use a nutritional calculator with the exact brands and measurements you're using with each recipe.