1. Preheat oven to 400° F.
2. Place one pastry sheet on a lightly floured surface.
3. Roll lightly to remove creases.
4. Use a pizza cutter to cut into 16 (2-inch) squares.
5. Slice the sausage into 1/4-inch circles. 
6. Place a sausage slice in the center of each square, pressing down firmly.
7. Repeat process with remaining pastry sheet and sausage.
8. Brush the top of the pastry with egg.
9. Transfer to a parchment-lined sheet pan.
10. Sprinkle with Cajun seasoning.
11. Bake for 20 minutes or until pastry is puffed and golden.
12. Stir together the mustard and mayonnaise in a small bowl.
13. Serve the sauce with the sausage puffs.

Note: If you roll the dough too much, it doesn’t puff as well.