Preheat oven to 350 degrees F. Coat a sheet pan with cooking spray and set aside.
Mix together ingredients for the cajun seasoning.
Cook the ground beef, sausage, and garlic in a large skillet over medium-high heat for about 8 to 10 minutes. Remove the meat from the skillet and set aside, draining off grease.
Add the celery, onion, and Cajun seasoning to the skillet and cook, stirring frequently, until tender, about 15 to 20 minutes.
Combine the meat and celery mixture in a large bowl. Let cool.
Cut the pie crust sheets into quarters. Place a small portion of the meat filling on one half of each piece of pie crust, leaving a 1/2-inch border around the outer 2 sides. Brush the edge with egg white and fold the dough into a triangle. Press down with a fork to seal in the meat filling. You should have 4 triangles from each pie crust.
Brush the tops with egg white and place on the prepared sheet pan and bake for 15 to 20 minutes or until golden.