1 cup sourdough starter
3 cups light malthouse flour
1 cup strong white flour
270 ml plum porter (/water)
1 tbspn oil
1 tbspn sugar
1 tspn salt
3/4 cup prunes, chopped
2 tbspn cacao nibs
1 tspn chipotle chilli flakes
First, make a levain (sponge) by stirring together the sourdough starter, 2 cups malthouse flour and the porter/water. You could do this in a bread mixer on the knead function. Leave overnight, or for a good 7 hours, until it's bubbling away nicely.
Now you can add the rest of the flour, the oil, sugar and salt. Knead for a good 10 minutes by hand, until the dough passes the window pane test, or if you're short of time, stick it in your mixer on the knead function. Now leave the dough covered until it's doubled in volume - typically about 4 hours (although if your house is as cold as ours at night, you can get away with an over-night rise).
Once it's risen enough, stretch it out to about 30cm by 20cm, then scatter the extra ingredients evenly over the surface. Knead them in as you would normally. As it doesn't need a full-on bashing at this point, I just fold the short edges over the toppings, one edge over the other, strech it so the previous long edges become the short edges and repeat the folding process. I do this several times until the toppings are sufficiently mixed through the dough. At this point, shape the dough into your loaf shape. If using a banetton or dutch oven, flour it and pop the dough in there, cover it and leave it for its final rise (about a couple of hours).
Once it's sufficiently risen, turn on the oven to maximum temperature and give your loaf it's final shaping: if using a dutch oven, I just smooth over the surface and tuck it under, using a silicone dough scraper - it keeps its air pockets in better this way.
When the oven is up to temperature, prepare the loaf to go in the oven: for a banetton-shaped loaf, grease a hot baking tray and pop the loaf on it, score it, then put it in the oven, with a tray of boiling water at the bottom of the oven; if using a dutch oven, score the loaf, spray its top surface with water then put the lid on and get it into the oven.
After 10 minutes, check the loaf colour. If it's looking gently browned, turn the oven temp down to 180' (170' fan-assisted), if it's a bit pale turn it down to 190' (180' fan-assisted). Leave to cook for 55 mins to an hour. Remove from the oven, put onto a wire rack and enjoy the aroma while you're waiting for it to be cool enough to savour the flavour.