Get your oven heating to 400°F and line a large baking sheet with parchment paper. This high heat is what creates those beautifully puffed, golden layers.
Combine the sausage meat, diced onion, minced garlic, sage, and black pepper in a mixing bowl. Use your hands to work everything together gently — you want it well mixed but not overworked, which can make the filling dense.
Roll the thawed puff pastry on a lightly floured surface until you have a neat 12x10 inch rectangle. Keep the rolling gentle and even — pastry that's been rolled too aggressively won't puff properly.
Using a sharp knife, cut the pastry lengthwise into 2 equal strips, each measuring about 12x5 inches. Clean cuts help the pastry rise evenly along the seams.
Divide your sausage mixture in half and shape each portion into a log that runs down the center of each pastry strip. Keep the logs compact and even — loose filling will leak out during baking.
Brush the pastry edges with beaten egg, then fold the pastry over the filling and press the seams firmly to seal. The egg wash acts like glue here, so don't skip it.
Cut each sealed log into 6 equal pieces using a sawing motion with your knife. Place them seam-side down on your prepared baking sheet, leaving space between each roll for even browning.
Brush the tops generously with the remaining egg wash and sprinkle with sesame seeds if you're using them. This gives you that bakery-perfect shine and crunch.
Bake until the pastry is deeply golden and the filling is cooked through — you'll hear gentle sizzling when they're ready. The bottoms should sound hollow when tapped.
⏱ 25 min