In a large bowl, combine ground beef, beaten egg, and breadcrumbs. Add grated onion, minced garlic, Worcestershire sauce, Dijon mustard, smoked paprika, dried oregano, and salt and pepper. Mix thoroughly for about 2-3 minutes until well incorporated.

Lay the meat mixture on a large piece of plastic wrap, forming it into a rectangle approximately 30 cm by 25 cm and 1 cm thick. Cover with another piece of plastic wrap and roll out with a rolling pin for an even surface.

In a separate bowl, mix cream cheese, chopped spinach, chopped sun-dried tomatoes, shredded mozzarella cheese, and grated Parmesan cheese. Spread the filling evenly over the meat rectangle, leaving a 2.5 cm border.

Using the bottom piece of plastic wrap, carefully lift and roll the meatloaf from the long side, keeping the filling inside. Pinch and seal the ends firmly.

Preheat your oven to 190°C (375°F). Transfer the Roulade Meatloaf to a parchment-lined baking sheet, seam-side down. Bake for 40-50 minutes until cooked through, reaching an internal temperature of 70°C (160°F).

Remove from oven and let it rest for 10-15 minutes. Slice into 4 cm pieces to reveal the spiral filling.