Preheat the Oven Preheat your oven to 400°F.
Line a muffin tin with paper liners or grease each cup lightly.
In a large mixing bowl, whisk together the freshly milled flour, cocoa powder, salt, baking soda, and baking powder until well combined.
In a separate bowl, whisk the sourdough discard, oil, egg, honey, buttermilk, and vanilla until smooth.
Pour the wet mixture into the dry ingredients and stir gently until just combined. The batter will be thick — that’s perfect for soft, tall muffins.
Add the chocolate chips and fold until evenly distributed.
Scoop the batter into the prepared muffin cups, filling each one nearly to the top for tall bakery-style muffins.
Bake at 400°F for 15 minutes, or until the tops are set and a toothpick inserted in the center comes out clean or with a few moist crumbs.
Let muffins cool in the pan for 5 minutes before transferring to a wire rack.
Serve warm and enjoy every melty chocolate in every bite.