In the bowl of a stand mixer fitted with the dough hook, combine the milk, yeast, and honey. Let sit 5-10 minutes, until bubbly on top. Add 4 tablespoons butter, eggs, 3 1/2 cups flour, and salt. Using the dough hook, mix until the flour is completely incorporated, about 4-5 minutes. If the dough is still sticky, add the additional 1/2 cup flour, adding more as needed until the dough is smooth to touch.Cover the bowl with plastic wrap and let sit at room temperature for 1 hour or until doubled in size.Meanwhile, mix the filling. In a bowl, combine the brown sugar and cinnamon. Butter a tube pan. Transfer the dough to a work surface and cut into 4 equal pieces. Working with 1 dough piece at a time, on a lightly floured surface, roll the dough into a large rectangle (roughly 14x10 inches). Spread 2tablespoons butter over the dough, then sprinkle with 1/4 cup cinnamon sugar and 2-4 tablespoons chocolate chips. Gently press the chips into the dough. Cut the dough lengthwise into 3 strips. Cut the strips crosswise into 4 strips each, making 12 squares (see above photo). Stack all 12 dough squares, 1 on top of the other. Repeat with the remaining 3 dough pieces and remaining butter. Arrange stacks in the buttered tube pan, standing up like little books, allowing gaps between dough pieces (see above photo).Cover the pan with plastic wrap, and let rise in a warm place until the dough almost reaches the top, about 1 hour. Preheat oven to 350° F. Bake until the bread is golden brown, 30 to 40 minutes. Let stand in the pan 5 minutes, then carefully remove. Serve warm.