Preheat the oven to 350 degrees. Prepare a cookie sheet by lining it with a baking mat or parchment paper.
In a large mixing bowl, beat shortening, butter, and both sugars on medium speed until fluffy.
Mix in the eggs, molasses, and vanilla extract until just combined.
In a food processor or blender, pulse 1 ½ cups of oats until it’s a flour-like consistency.
In a separate medium bowl, whisk together the dry ingredients: flour, the “oat flour”, oats, cornstarch, baking soda, baking powder, ground cinnamon, and salt.
Add the dry ingredients to the wet ingredients. Mix until well combined on low-medium speed.
Using a 1 tablespoon cookie scoop, place scoops of dough onto the cookie sheet about 2 inches apart.
Bake the cookies for 10 minutes. Transfer cookies to a cooling rack and let cool completely