Preheat Oven: Set your oven to 180°C (350°F).

Grease Baking Sheet: Lightly grease a 22 cm diameter baking sheet with butter.

Roll Out Pastry: Roll out the puff pastry into a large rectangle on a lightly floured surface.

Spread Sauce: Evenly spread the tomato sauce over the puff pastry.

Add Ingredients: Sprinkle the diced bacon, chopped spring onions, and grated Parmesan cheese evenly over the sauce.

Season: Season with salt, black pepper, and sweet paprika.

Roll Pastry: Carefully roll the puff pastry with the filling into a tight log.

Cut into Slices: Using a sharp knife, cut the log into slices about 2 cm thick to create the snails.

Arrange Snails: Place the snails cut-side down on the greased baking sheet.

Brush with Egg: Brush the tops of the snails with the beaten egg to give them a golden finish.

Bake: Bake in the preheated oven for 45 minutes or until the snails are golden brown and cooked through.