Mix starter, water, sugar, salt, flour. Rest 30 mins.

Do 3 sets of stretch and folds (30 mins apart).

Add blueberries and chocolate on second stretch and fold.

Then, bulk ferment until doubled.

Preshape and rest 20 mins.

Final shaping and cold proof.

Preheat oven 450.

Add bread, covered and immediately lower to 425. Bake 23 mins.

Uncover, lower to 400 and I baked 15 mins. more.