Preheat the oven to 350 degrees F.
Line a baking sheet with parchment paper or silicone baking mat. Set aside.
In a medium mixing bowl, whisk together flour, soda and salt. Set aside.
In a medium saucepan, melt butter on low. Remove from heat.
Whisk in cocoa powder and both sugars.
Add yogurt and vanilla and whisk until smooth.
Stir in the dry ingredients.
Stir in mint chips.
Drop 1,5 tablespoons of dough onto prepared baking sheet.
Bake cookies for 8 to 10 minutes (9 minutes was the magic number for me; do not bake for more than 10 minutes).
Cool for 3 minutes on the sheet, gently transfer onto a cooling rack.