In the bowl of a stand mixer, combine the warm milk, yeast, honey, 4 eggs, all-purpose flour, and salt. Using the dough hook, mix until the flour is completely incorporated, about 4 to 5 minutes. Add 4 tablespoons of room temperature butter and mix until combined, about 2 to 3 minutes more.
Cover the bowl with plastic wrap and let sit at room temperature for 1 hour or until the dough has doubled in size. This is a critical step, as it allows the flavors to develop and the dough to rise.
Once the dough has risen, punch it down and roll it out onto a lightly floured surface, creating a large rectangle that’s about 14 by 14 inches. Lay thin slices of cold butter all over the surface of the dough, pressing gently to adhere.
Fold one half of the rectangle towards the center and then fold the other half over the top of the first layer, forming three layers of dough (similar to an envelope). Wrap the dough in plastic wrap and transfer it to the freezer for 15 to 20 minutes until chilled. Chilling the dough makes it easier to work with.
Meanwhile, butter two 9 by 5 inch bread pans. In a small bowl, mix together brown sugar, granulated sugar, and cinnamon to create the filling for the bread.
After chilling, remove the dough from the freezer. Roll the dough into a rectangle (about 14 by 14 inches) again. Spread 4 tablespoons of softened butter over the dough and sprinkle half of the cinnamon sugar mixture over the top. Layer the peach slices over the dough in a single layer and then sprinkle with the remaining cinnamon sugar.
Starting at the edge of the dough closest to you, pull the edge up and over the filling, carefully rolling the dough into a log while keeping it tight. When you reach the edge, pinch along the edges to seal. This helps to lock in all the delicious filling.
Cut the dough into 6 rolls and place them cut side up in the prepared pans. Cover and let rise for 45 minutes to 1 hour, allowing them to puff up.
Preheat your oven to 350 degrees F. Once risen, place the bread pans on a rimmed baking sheet and bake for 30 to 35 minutes, or until the tops are lightly browned. The heavenly aroma will fill your kitchen! Let cool in the pans for 5 minutes, then flip the breads out onto a cooling rack. Serve the Flaky Pull Apart Cinnamon Peach Brioche Bread warm or cold, and enjoy every bite.
