Melt the chocolate and butter and stir until smooth. Whisk the flour, baking powder, cinnamon, and salt in a medium bowl. In a large mixing bowl, beat the eggs with a hand mixer until they are foamy.
Add sugar a few tablespoons at a time and beat well. Once all sugar is added, beat egg mixture until it’s light in color and thickened. Add melted chocolate to egg mixture and then beat in dry ingredients. Bake.