-
1
Combine the chestnut flour and buckwheat flour in a bowl, then add the egg yolks, milk, caster sugar and a pinch of salt. Whisk to a smooth, lump-free batter, working out any pockets of flour that cling to the bottom of the bowl, so the dense mountain flours are fully hydrated and the finished schmarren has no raw, gritty patches. The batter will be noticeably darker and heavier than a plain-flour batter.
-
2
In a separate, clean bowl, beat the egg whites to stiff peaks — the whites should hold a firm, upright peak when the whisk is lifted and show no liquidity at the base. Fold one-third of the whites into the batter first so the batter loosens enough to accept the remainder without resistance, then fold in the rest in two additions with a large spoon or spatula, using slow, deliberate strokes only so the aeration of the whites — the sole source of lightness against two dense mountain flours — is not beaten out irreversibly. This is where the dish lives or dies; the batter must retain visible volume when it goes into the pan.
-
3
Melt the butter in a wide, heavy-based ovenproof pan over a medium flame until it foams and subsides, so the moisture has cooked off and the butter will colour the base of the schmarren rather than steam it. Pour in the batter in one even layer and cook without disturbance until the underside is fully set and a deep golden-brown: the edges will appear dry and matte, the centre will have lost its raw sheen, and the pan will release a toasted, nutty aroma.
-
4
Using two forks, tear the schmarren into irregular pieces of 3–5 cm directly in the pan, so each piece gains new exposed surfaces that can take on colour and caramelised edges. Toss and turn the pieces continuously over the heat until all cut and torn surfaces are golden, checking that the pieces release cleanly from the pan and move freely — any sticking indicates the base was not sufficiently set before tearing began.
-
5
Dust the icing sugar evenly over the torn pieces in the pan so every surface has a chance to caramelise rather than leaving the sugar pooled in one spot. Allow it to melt and caramelise briefly — 30 to 60 seconds — until the sugar produces a faintly bitter, caramel scent and the pieces glisten, then remove from the heat immediately.
-
6
Transfer at once to warm plates and serve with the lingonberry jam alongside. The schmarren must reach the table immediately, as the crisp torn edges soften within minutes of leaving the heat.