Place the cooled paste into a large bowl. Add the water, oil, sugar, mixed spice and sourdough. Stir together briefly to combine, mashing the paste up slightly as you do this.
210 g (1 cup minus 2 tbsp) water, 60 g (1/4 cup) vegetable oil, plus extra for the bowl, 50 g (1/4 cup) granulated sugar, 2 tbsp mixed spice, 90 g sourdough starter
Add the flours and salt to the dough. Stir together until you get a shaggy dough.
250 g (2 cups) white bread flour, plus extra for kneading, 200 g (1 2/3 cup) wholewheat bread flour, 1 tsp salt
Tip out onto a clean work surface and knead for 8-10 minutes, dusting with extra white bread flour as needed to prevent it sticking, until smooth and elastic.
Pat out into a circle then sprinkle over the mixed dried fruit. Roll the dough up into a log, like a Swiss roll cake, then coil up into a ball.
150 g mixed dried fruit
Drizzle a bit of extra vegetable oil into the bowl you were using earlier. Add the dough to the bowl and turn it to coat with the vegetable oil.
Cover the bowl with a damp tea towel (or a shower cap). Leave at room temperature for 8-12 hours or until the dough has doubled in volume (I usually leave it overnight).
If you find the dough hasn't doubled in volume in that time, place somewhere warm (e.g. an oven switched onto the lowest heat for 2 minutes then turned off) for an hour or two to help things along.