Brown the ground beef in a skillet over medium heat. Add onion and cook for 2–3 minutes.
Stir in garlic, tomato paste, Italian seasoning, paprika, salt, and pepper. Cook for another 1–2 minutes. Let the mixture cool slightly.
Preheat oven to 400°F (200°C). Roll out the puff pastry on a lightly floured surface.
Spread the cooled beef mixture over half of the pastry and sprinkle evenly with mozzarella and cheddar.
Fold the other half of the pastry over the filling and gently press down.
Cut into strips about 1 inch wide. Twist each strip several times and place on a parchment-lined baking sheet.
Brush with beaten egg and sprinkle with sesame seeds or Parmesan if desired.
Bake for 15–20 minutes, until puffed and golden brown.
Cool for a few minutes before serving.
