Melt the butter and milk in a saucepan until warm. Put into a large bowl.
Add the yeast and the sugar and gently mix together. Set aside for 10 minutes until the mixture is foamy.
In a medium bowl, whisk the eggs, sugar, and spices together.
Add 1 cup of flour to the yeast bowl and stir. Add the egg mixture and mix to combine. Add the remaining 2 1/2 cups of flour until a sticky dough forms.
Turn out the dough onto a floured surface and knead for 7-10 minutes until the dough is smooth and elastic. You may need to add some more flour if the dough is too sticky to work with. Place the dough in a large, well oiled bowl, cover with plastic wrap, and let it rise for 2 hours in a warm place.
In a small bowl, combine the sugar and cinnamon for the filling. Line a 9 inch loaf pan with parchment paper and spray with cooking spray.
After the dough has risen, turn out the dough onto a lightly floured surface. Roll out the dough into a large rectangle that is wide enough to fit in loaf pan. Pour the melted butter over the rectangle, and spread using a pastry brush to all ends of the rectangle. Sprinkle the cinnamon sugar mixture over the dough and then sprinkle with the chocolate.
Roll up the dough (like you do with cinnamon rolls) and pinch the end so that the seam is sealed. Place the dough into the loaf pan seam side down, and cover with plastic wrap and let it rise in the loaf pan for 30 minutes.
Preheat the oven to 350 F. Brush the loaf with your egg wash using a pastry brush. Place it in the oven and bake for 40-50 minutes, or until the loaf sounds hollow. Remove from the oven and let cool for 10 minutes before taking it out of the pan, then place on a cooling rack and let it cool completely before slicing. Enjoy!
