The panino con strudel di mele, the Alto Adige Apfelstrudel treated as a filling, is a sandwich only by behaviour. The strudel itself is the Tyrolean classic: thin pulled pastry rolled around spiced apple, raisins, pine nuts, and breadcrumbs, baked until the shell is crisp and the fruit inside has slumped to a soft, sweet, cinnamon-edged compote. Set into bread it stops being a dessert plate and becomes something you hold and eat in the hand, which is the only sense in which it qualifies here. It is a sweet outlier in a catalogue of savoury panini, and the honest description is that the bread is doing nothing the strudel pastry was not already doing better.
The craft, such as it is, is about not destroying a fragile thing. The strudel is held warm or at room temperature, never fridge-cold, because cold sets the butter in the pastry hard and mutes the spice in the apple. A soft, mild bread is the only sensible carrier, a sweet roll or a plain brioche, since any crust with real bite fights the delicate layered pastry and any salt or oil in the bread argues with the cinnamon and raisin. The filling brings its own moisture from the cooked apple, so the bread stays on the dry side and the assembly is kept loose; pressed or wrapped tight, the strudel's leaves shatter and the compote squeezes out. It is closer to carrying a slice of cake in a napkin than to building a sandwich, and it works only if treated with that much restraint.
There is not much to vary into, and what exists stays in the Germanic north. The strudel can be met with a smear of unsweetened cream, served alongside rather than inside as the proper Tyrolean dessert, or swapped for the festival breads Zelten and Buchteln. Those are their own preparations and deserve their own articles rather than being crowded in here.