Preheat oven to 356F (180C) and prepare a muffin trayor mini-muffin tray (grease or add cupcake liners).
In a medium bowl, whisk the dry ingredients (flour,sugar, cacao powder, baking soda and salt).
In a microwave safe bowl, add the dark chocolate and oil and melt in 30 second increments, mixing in between, until the chocolate is fully melted.
Add yogurt, eggs, vanilla and whisk until combined.
Add hot water to the chocolate mixture.
Pour liquid chocolate mixture into the dry ingredients and whisk until incorporated
Scoop the cupcake batter into the muffin trayand bake for 20-22 minutes until a toothpick comes out clean and the muffins are golden on the edges. Let them cool a bit and move to a wire rack.