Use a sharp knife to remove the casing from the sausages and finely chop the meat inside.: The first time you slice through sausage casing you notice a soft, slightly springy resistance, followed by the release of seasoned meat that smells savory and warm. Finely chopping the meat rather than leaving large chunks ensures even distribution through each roll, so every bite is balanced. You want small pieces so the filling pipes smoothly and forms a cohesive log when placed on the pastry. A common mistake is using a dull knife which tears the casing and makes a mess, or chopping too coarsely which creates uneven texture. If the meat feels sticky from handling, chill it briefly to firm it up before continuing.
In a large bowl, combine the sausage meat, pepper, apple sauce, and sage leaves. Mix well.: When you stir these items together the scent of sage lifts and the apple sauce tames the sausage richness. Mixing releases juices and binds the components so the filling becomes cohesive. Use your hands or a spoon to make sure the chopped sage disperses evenly and the pepper is distributed. If the mixture seems too wet, rest it in the fridge for ten minutes to firm; if too dry, a teaspoon more apple sauce can help. Avoid overmixing which can make the texture dense instead of tender.
Transfer the mixture to a piping bag.: Moving the filling into a piping bag smooths the assembly process and creates neat uniform logs on the pastry, which helps the rolls bake evenly. As you fill the bag you should feel the mixture settle, and a quick squeeze will show you how it will behave when piped. If the mixture resists, it might be slightly stiff, in which case allow it to sit at room temperature for a few minutes to soften. A common misstep is using a bag without cutting an appropriate opening, resulting in chunks getting stuck; choose an opening just large enough to accommodate the mix.
Place a sheet of puff pastry on your work surface with the long side facing you.: Laying the puff pastry with the long side toward you gives you the most efficient space for rolling. The pastry should be cold and slightly firm to the touch, and you will notice a faint doughy smell with buttery undertones. Working quickly preserves the butter layers which create lift during baking. If the pastry feels tacky or soft, pop it back in the fridge to chill for ten minutes. A mistake is rolling on a warm surface which causes the pastry to stick and lose structure.
Spread half of the sausage mixture down the center of the pastry and brush the surface with the egg yolk.: As you pipe the filling down the center, the contrast of pale pastry and darker filling becomes visible. The act of brushing the pastry with the egg wash adds moisture that helps the seam stick and promotes browning. Keep the filling in a neat line so you can fold the pastry cleanly. Avoid overfilling which can cause leakage during baking, and be sure to leave a margin at the edges for sealing.
Fold the bottom part of the pastry over the sausage mixture, pressing firmly to seal. Trim any excess dough.: Folding creates a snug pocket; press firmly so the seam holds, and any excess should be trimmed for tidy rolls. As you press the seam you may hear a faint crinkle as layers compress, which is normal. Trimming ensures uniform pieces and helps prevent uneven browning. Do not skip sealing, since poorly sealed seams can open during baking and spill filling into the pan.
Cut the rolled pastry into 9 equal pieces and press the edges with a fork to seal.: When you slice the roll the visual of tight spirals appears, and you can see the filling encased by layers of pastry. Pressing the edges with a fork not only seals but leaves a decorative imprint. Aim for even pieces so they cook at the same rate. A common error is uneven cutting which leads to mismatched baking times; use a ruler or gentle measuring to keep sizes consistent.
Brush the tops with egg yolk and sprinkle with poppy seeds.: Brushing the tops creates that glossy amber finish and helps the poppy seeds adhere. As the glaze hits the surface you can see it darken slightly, signaling an even bake later on. The seeds toast and add a tiny nutty crunch when baked. Over brushing will pool the wash and may cause soggy spots, so use a light, even layer.
Repeat the process with the second sheet of puff pastry.: Repeating ensures you use all the filling and makes a second batch with the same visual consistency. Working methodically keeps the workflow smooth, and the second sheet often goes faster since you know the rhythm. If the pastry warms while working, chill the assembled rolls briefly before cooking. Rushing this step can lead to sloppy seams and less lift.
Place the rolls in the air fryer and bake at 180°C/356°F for 20 minutes. Alternatively, you can bake the rolls in the oven.: As they bake in the Air Fryer you will notice the pastry turning golden and you may hear a faint crackle as layers separate and crisp. The aroma of toasting poppy seeds and warming sausage fills the kitchen, which is a good cue to peek. The oven alternative gives a similar result though timing can vary, so check for a deep golden color. A common mistake is opening the cooker too often which lets heat escape and reduces puff; resist frequent peeks and rely on color as the main indicator of doneness.