Pre-heat oven to 350° (180° celsius). Grease 6 tin donut pan.
In a medium bowl whisk together flour, baking powder, baking soda, salt, sugar and cocoa.
In a small saucepan over low heat melt butter, remove from heat and let cool slightly.
In a medium bowl whisk together egg, coffee, milk, yogurt and vanilla, add melted butter and combine.
Mix the wet ingredients into the dry ingredients and mix just until flour is absorbed, it will be a little lumpy but that is perfect.
Fill doughnut pan until almost full. Bake for approximately 8-10 minutes (check with a toothpick for doneness), cool in pan and then remove to wire rack to cool completely before drizzling with the glaze.
FOR THE GLAZE
In a small bowl add whipping cream, mascarpone and icing sugar, beat or whisk until smooth, if it's too thin add more sugar if too thick add more cream. Top with glaze. Enjoy!
For room temperature ingredients remove from the fridge 30-45 minutes before using.