Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper and lightly coat with cooking spray.
In a large skillet, cook the ground beef over medium heat until browned and cooked through, about 5-7 minutes. Drain excess fat.
Stir in the taco seasoning and salsa, cooking for an additional 2-3 minutes until combined. Remove from heat and let cool for a few minutes.
Unroll the crescent roll dough on a clean surface and pinch the seams together to form a rectangle.
Cut the dough into strips, about 2 inches wide.
Spoon a small amount of the beef mixture onto each strip, followed by a sprinkle of cheddar and mozzarella cheese.
Fold the dough over the filling, pressing to seal the edges. Optionally, use a fork to crimp the edges for a decorative touch.
In a small bowl, whisk the egg and brush the mixture over each taco stick for a golden finish.
Place the taco sticks on the prepared baking sheet and bake for 15-20 minutes or until they are golden brown.
Allow them to cool slightly before serving.