Preparation
Make the cake:
1. Preheat the oven to 175°C. Grease a Bundt pan (or your preferred pan) very well with butter, and cover the butter with a light coating of flour. (Use the button to cut the ingredients in half and use a rectangular loaf pan.)
2. In a small saucepan, combine the butter, cocoa powder, salt, and water and place over medium heat. Cook stirring until melted and combined. Take it off the heat and let it cool for 10 minutes.
3. In a large bowl, mix the flour, sugar, and baking soda.
4. Make sure the butter mixture is cold, pour it in with the dry ingredients, and beat until just combined.
5. Add the eggs, beating until completely blended. Add the Greek yogurt. Beat until smooth. The result will be very liquid.
6. Put the dough in the prepared pan and bake until a toothpick inserted in the center of the cake comes out clean, 35 to 45 minutes, depending on the oven and size of the pan.
7. Let the cake cool in the pan for 30 minutes and then pour it onto a serving plate. Remove the pan and allow the cake to cool completely before frosting.
Make the glaze:
1. While the cake is cooling, make the chocolate frosting. Place the finely chopped chocolate and the cream in a glass or metal bowl. Put it on top of a saucepan with water over medium heat to make a bain-marie. The steam will heat the ingredients as you stir, until everything is dissolved and smooth.
2. Pour the frosting over the cooled cake, allowing it to drip down the sides. Cut into pieces and serve.