Preheat your oven to 400°F and line a baking tray with parchment paper.
In a small skillet, sauté 1 finely chopped onion in a splash of olive oil for about 4 minutes or until soft. Add 1 clove of minced garlic and cook for 30 seconds more. Remove from heat and let cool slightly.
In a bowl, combine 1 pound of ground sausage meat, sautéed onion/garlic, ½ cup of Parmesan cheese, 1 teaspoon of dried basil, ¼ teaspoon of black pepper, and 1 egg. Stir the ingredients together until everything is well combined.
Gently unfold the puff pastry on a lightly floured surface and roll it into a rectangle approximately 12 x 9 inches.
Shape the sausage mixture into a long log down the center of the first pastry. Prepare the egg wash by beating 1 egg and 1 teaspoon purified water until combined. Brush one edge of the pastry with the egg wash.
Fold the pastry over the sausage, and pinch the seams closed.
Cut into 1 to 1½-inch pieces, aiming for 12 to 15 bites. Brush the tops with the remaining egg wash. Arrange rolls seam-side down on the tray.
Bake for 23–25 minutes, until the pastry is golden and puffed, and the sausage is cooked through and reaches an internal temperature of 160°F.
Let the sausage rolls cool for 5 minutes, then enjoy them warm. Serve with your favorite marinara, pizza, or spaghetti sauce for dipping.