Mix the flour and 300g water in a large bowl until no dry bits remain. Cover and rest 1 hour.

Add the starter, salt, and remaining water a little at a time until the dough is soft and cohesive. Cover and rest 30 minutes.

Every 30 minutes, grab the dough from one side, stretch it up, and fold it over the centre. Turn the bowl a quarter-turn and repeat until you've done all four sides. Do four rounds of these folds over the next 2 hours to build strength.

Let the dough bulk ferment for 2 hours — it's ready for the next stage once it has risen about 50% and feels puffy, with a few bubbles on the surface or around the edges, light but not over-proofed, and when you lift the edge, it stretches without tearing, like soft elastic.

Now It's Time For The Fillings: Lightly flour a clean surface. Gently tip the dough out and stretch it into a thin rectangle, taking care not to tear it. Evenly scatter about 70% of the sifted blueberry powder and goat cheese chunks over the surface.

Fold one long side toward the centre, sprinkle a little more filling, then fold the other long side over it, like folding a letter.

Add the remaining filling, then fold the top and bottom in the same way to form a neat parcel.

Tuck the edges under to create a tight ball.

Line a medium mixing bowl with a clean tea towel generously dusted with rice flour. Place the dough seam-side up, cover, and refrigerate for 8–12 hours.

8–12 Hours Later: Preheat the oven and a Dutch oven (or heavy lidded pot) to 230°C (450°F). Invert the dough onto baking paper so it's seam-side down, score the top, and add 4–5 ice cubes under the baking paper.

Cover and bake for 30 minutes. Remove the lid and bake another 20–25 minutes until the crust is deep golden and internal temperature is about 96°C.