Trentino-Alto Adige — the krapfen tradition throughout the region reflects the centuries of Hapsburg Austrian rule. The word krapfen is documented in Austrian sources from the 8th century; the specific Tyrolean version with jam filling and vanilla sugar dusting was established in the 18th-century Viennese pastry tradition.
Krapfen are the Tyrolean deep-fried yeasted doughnuts, filled with jam (typically preiselbeeren — lingonberry or rowanberry jam, or apricot jam) and dusted with vanilla icing sugar. They are prepared throughout the Alpine arc (Austria, Bavaria, Trentino, and Alto Adige) for Carnival, fat Tuesday, and winter celebrations. The Trentino-Alto Adige version uses the typical Austrian-origin formula: a very enriched dough (flour, eggs, butter, sugar, yeast, a small amount of lard) that produces a light, pillowy, golden doughnut with a white equator (the un-fried band at the middle) that indicates correct frying.
A properly fried krapfen is one of the great simple pleasures of Alpine winter — the exterior is golden and yields slightly to the touch; the interior is pillowy and soft; in the centre, the jam is warm and fruity. The vanilla icing sugar dissolves against the warm dough. It is the taste of Carnival in the Dolomites.
The dough: 500g flour, 2 eggs, 60g butter, 50g sugar, 15g yeast, 200ml warm milk, salt, and lemon zest. Knead 10 minutes — the dough should be smooth, soft, and slightly tacky. First rise (1 hour). Shape into balls (60g each). Rest 10 minutes. Roll to 1cm thickness, cut into rounds (8cm). Place a small amount of jam in the centre of half the rounds. Cover with the remaining rounds, pressing the edges firmly to seal. Second rise (30-45 minutes — the rounds should puff noticeably). Fry in lard or oil at 170°C for 2-3 minutes per side — do not rush. The white equator should form during frying (the middle, which doesn't touch the oil, remains pale). Drain, dust with vanilla icing sugar.
The white equator is the visual indicator of correctly fried krapfen — it forms because the doughnut floats in the oil and the central band never touches the hot oil surface. To encourage it, ensure the oil is not too deep (the krapfen should barely float rather than being fully submerged). Preiselbeeren (lingonberry jam) is the traditional Tyrolean filling; rose hip jam is also classic.
Oil too hot — the exterior browns before the interior is cooked and puffed. Insufficient second rise — under-proofed krapfen are dense rather than pillowy. Not sealing firmly — jam leaks into the oil. Over-filling with jam — too much jam creates too much steam and bursts the seal.
Carol Field, The Italian Baker; Slow Food Editore, Trentino-Alto Adige in Cucina