Line a baking sheet with a silicone mat or parchment paper. Cube the butter and set in the freezer while you prepare the other ingredients.
Sift the dry ingredients together. (2 cups flour, 1/4 cup cocoa powder, 1/4 cup sugar, 1/4 teaspoon salt, 1 tablespoon baking powder, 1/2 teaspoon cloves.)
Whisk the egg first, then whisk together all of the wet ingredients. (1/2 cup yogurt, 1/4 cup milk) in the same bowl.
Using a pastry cutter, cut the butter into the dry ingredients until it resembles pea gravel. (You can also shred the butter with a cheese grater.) Add the wet ingredients to the dry ingredients. Add the 1 cup of chocolate chips and mix until the mixture starts coming together. It will be a bit crumbly, this is ok. At this point, I like to form the dough ball with my hands. You may need to add a bit of extra milk if the dough seems too dry. You shouldn't need more than 2 tablespoons, if that.
Once you form the dough ball, flatten it in your hands, fold it in half, and repeat the process a few times. Form the dough into a ball and split it in half, forming those halves into dough balls. Flatten them into 6-inch discs on the baking sheet, about 1 inch thick. Cut the discs into 6 (mostly) equal pieces. Pull the pieces about 2 inches apart so the sides don't bake up too soft.
Place the scones in the fridge for 20 minutes, Preheat the oven to 400 F. I like to use this time to clean up.
After 20 minutes, bake the scones for 20 minutes. The scones will have increased in volume due to the flakiness and will be a nice, chocolate color. They will have a flaky interior.
While the scones are baking, make the glaze. In a small bowl, mix together 3/4 cup powdered sugar, 1 tablespoon cocoa powder, and 4 tablespoons heavy cream/milk. The glaze should be thin enough to drizzle off the spoon, yet thick enough not to be runny.
Once the scones are done baking, let them rest for 10 minutes before turning them out onto a baking rack to cool completely. Feel free to enjoy a warm scone, but you want them to be fully cooled down before adding the glaze or it will just melt off.