Preheat the oven to 175°C /350°F.
Prepare the chocolate. Chop the chocolate using a knife into small pieces. The pieces should be ¼-inch (½ cm) and smaller in size.
Mix together in a bowl the dry ingredients (flour, cocoa powder, cinnamon) and set aside.
Butter and flour a bundt pan.
Cream butter together with sugar. Using your electric mixer with the whisk attachment on beat for at least 8-10 minutes until very creamy.
Incorporate the eggs one by one. Waiting until each one is fully combined before adding the next one.
Alternately mix in the dry ingredients and red wine. Starting with the flour and then the wine. Keep beating over lower speed until fully incorporated. Turn off the mixer.
Fold in the chopped chocolate.
Transfer the mixture to the prepared pan.
Bake for 40 to 45 minutes. Test with a toothpick to ensure the cake is baked at the center.
Allow the cake to cool for about an hour. Then trim to smoothen the surface a bit (optional).
Overlap the cake on a serving plate. Or on a cooling rack.