These more-ish scrolls are best served on the day they're made.
You can bake them a few hours ahead then warm them in the oven for
a few minutes just before serving.
1onion, thinly sliced1 tbspolive oil250 gm (1 2/3 cups)bread flour100 gm (2/3 cup)rye flour10 gmbrown sugar7 gm (1 sachet)dried yeast2 tbspfinely chopped chives70 gm eachGruyère and aged Cheddar, coarsely grated125 ml (½ cup)milk, plus extra for brushing
Stir onion and oil in a saucepan over medium-high heat until tender (4-5 minutes), set aside. Combine flours, sugar, yeast, chives, 50gm cheddar, onion mixture and 2 tsp sea salt in the bowl of an electric mixer fitted with a dough hook. Warm milk and 90ml water in a saucepan over low heat until lukewarm, add to flour mixture, knead until smooth and elastic (4-5 minutes). Transfer to a lightly oiled bowl, cover and stand in a warm place until doubled in size (45 minutes-1 hour).
Meanwhile, preheat oven to 180C. Knock back dough and roll out on a lightly floured surface to a 20cm x 40cm rectangle. Scatter with remaining cheeses then roll to form a long cylinder. Cut into 8 pieces, place cut-side down on an oven tray lined with baking paper, stand until slightly risen (10 minutes). Brush tops with milk and bake until golden (20-25 minutes). Serve warm.