Soak raisins in rum (or apple juice ) for at least 30 minutes.
Separate the eggs. Whisk yolks with melted butter, vanilla, sugar, and salt. Add flour and milk gradually until smooth.
Beat the egg whites to soft peaks, then gently fold into the batter.
Heat 15g butter in a large non-stick pan. Pour in the batter, scatter over the raisins, and cook 5–6 minutes until the base is golden.
Cut the pancake into quarters, flip, and cook another 2–3 minutes.
Tear into shreds with spatulas, add the rest of the butter and sugar, and caramelise for 1–2 minutes.
Dust with icing sugar and serve immediately (plum compote or apricot jam!)
