Activate the Yeast: In a large bowl, combine the warm milk, 1 tablespoon of the granulated sugar from the dough ingredients, and the active dry yeast. Stir gently and let it sit for 5-10 minutes until foamy.

Prepare the Dough: To the foamy yeast mixture, add the remaining granulated sugar, salt, melted butter, egg, and vanilla extract. Whisk until well combined. Gradually add the 3 cups of flour, mixing with a wooden spoon or a stand mixer with a dough hook attachment until a shaggy dough forms.

Knead the Dough: Turn the dough out onto a lightly floured surface and knead for 8-10 minutes until it’s smooth, elastic, and no longer sticky.

First Rise (Bulk Fermentation): Lightly grease a clean large bowl. Place the dough in the bowl, turning it once to coat. Cover the bowl tightly with plastic wrap or a clean kitchen towel. Let it rise in a warm, draft-free place for 1 to 1.5 hours, or until doubled in size.

Prepare the Blueberries: While the dough is rising, gently toss the fresh or frozen blueberries with 1 tablespoon of flour in a small bowl.

Prepare the Cream Cheese Filling: In a medium bowl, combine the softened cream cheese, ¼ cup granulated sugar, 1 tablespoon flour, lemon zest (if using), and ½ teaspoon vanilla extract. Beat with an electric mixer on medium speed until smooth.

Deflate and Incorporate Blueberries: Once the dough has doubled, gently punch it down to release the air. Turn the dough out onto a lightly floured surface. Gently flatten it into a rectangle. Scatter the floured blueberries over the dough. Fold the dough over itself a few times and gently knead for about 1-2 minutes.

Shape the Loaf: Roll or gently pat the dough into a rectangle, approximately 12×16 inches. Spread the prepared cream cheese filling evenly over about two-thirds of the dough.

Fold and Roll the Loaf: Fold the un-creamed third of the dough over the middle third. Then, fold the remaining cream-cheesed third over the top. Starting from one of the short ends, tightly roll the dough into a log.

Second Rise (Proofing): Line a round proofing basket (banneton) or a 9-inch round bowl with parchment paper. Carefully transfer the shaped loaf, seam-side up, into the prepared basket/bowl. Let it rise in a warm place for 45-60 minutes.

Preheat Oven and Dutch Oven: About 30 minutes before the end of the second rise, preheat your oven to 450°F (232°C) with a Dutch oven inside.

Score and Bake: Carefully remove the hot Dutch oven from the oven. Using the parchment paper overhangs, gently lift the loaf from the basket and lower it into the hot Dutch oven. Score the top of the loaf with a single, deep cut.

First Bake (Covered): Place the lid on the Dutch oven and bake for 30 minutes.

Second Bake (Uncovered): Remove the lid from the Dutch oven. Reduce the oven temperature to 425°F (220°C). Continue baking for another 15-25 minutes.

Cooling: Carefully remove the loaf from the Dutch oven using the parchment paper handles. Transfer it to a wire rack to cool completely before slicing.