Autolyse: In a large bowl, whisk starter and lukewarm water until milky. Add bread flour, whole wheat flour, and strawberry powder. Mix until a shaggy dough forms. Cover and rest for 45-60 minutes.

Add Salt: Sprinkle sea salt over the dough with a tiny splash of water. Knead and fold the salt into the dough for 3-5 minutes until incorporated. Cover and rest 30 minutes in a warm spot.

Fold 1: Perform a set of stretch and folds by pulling each side of the dough up and over the center. Cover and rest 30 minutes.

Fold 2 (Lamination & Inclusions): Gently stretch the dough into a large thin rectangle on a lightly misted counter. Sprinkle the chopped strawberries and white chocolate chips evenly. Fold into thirds, roll up, return to bowl. Cover and rest 30 minutes.

Folds 3 & 4: Perform two sets of gentle coil folds, resting 30 minutes between each. The dough should feel strong and elastic.

Bulk Fermentation: Let the dough rest undisturbed until it has increased in volume by 50-75%, appears puffy, and shows surface bubbles (about 2-4 more hours).

Pre-shape & Shape: Turn dough out, round loosely, and rest 20 minutes. Shape into a tight boule or batard, ensuring no chocolate chips are exposed on the outer skin. Place seam-side up in a rice-floured banneton.

Cold Retard: Cover the banneton tightly and place in the refrigerator for 12 to 24 hours.

Bake Prep: Preheat oven to 450°F (230°C) with a Dutch oven inside for 1 hour.

Score and Bake: Turn the cold dough out onto parchment paper. Score the top with a lame. Transfer to the hot Dutch oven. Bake covered for 25 minutes.

Finish Bake: Remove the lid and bake for another 20-25 minutes until the crust is deep golden brown.

Cool: Transfer to a wire rack and cool completely for at least 2-3 hours before slicing to prevent a gummy crumb.