In a large mixing bowl, combine all-purpose flour, granulated sugar, and sea salt. Cut in cold unsalted butter until the mixture resembles coarse crumbs.

In a separate bowl, activate the active dry yeast in warm whole milk for about 5 minutes. Then, mix everything until a shaggy dough forms.

Wrap the dough tightly in plastic wrap and refrigerate for at least 4 hours.

After chilling, lightly dust your work surface with flour and roll out the dough into a large rectangle, about 1/2 inch thick.

Perform a letter fold by bringing one end of the dough towards the center and then folding the other end over.

Rest the folded dough in the fridge for 30 minutes to maintain the cold temperature. Repeat this process two more times for a total of three folds.

Make the cream cheese filling by beating together softened full-fat cream cheese, granulated sugar, egg yolk, lemon juice, and vanilla extract until smooth and creamy.

Once the dough is properly laminated, roll it out into a rectangle and cut strips at an angle along the edges, leaving a center strip for the filling.

Spread the cream cheese mixture evenly down the center, then sprinkle fresh blueberries over the filling.

Carefully fold the angled dough strips over the filling alternately, forming a braided pattern, and pinch the ends to seal.

Place the assembled Blueberry Cream Cheese Pastry Braid on a parchment-lined baking sheet.

Brush the surface with an egg wash made from whisking a large egg with a splash of water.

Cover the braid loosely with plastic wrap, and let it proof at room temperature for 30 to 60 minutes.

Preheat your oven to 375°F (190°C). Once proofed, remove the plastic wrap and bake the pastry braid for 20 to 25 minutes.

While the pastry cools, prepare the vanilla icing by mixing powdered sugar with whole milk and vanilla extract until you reach a smooth, pourable consistency.

Once the Blueberry Cream Cheese Pastry Braid is completely cool, drizzle the icing over the top.

Allow the icing to set for about 10 minutes before slicing.