Preheat the oven to 375ºF.
Add sourdough discard to a small bowl with melted butter and liquid coconut oil. Whisk together until mostly combined. Add the buttermilk, sugar, egg, vanilla extract and whisk until completely combined. Set aside.
In a mixing bowl, whisk together all-purpose flour, baking powder and salt. Pour the liquid ingredients on top of the flour mixture and stir gently a few times until thoroughly moistened. A few streaks of flour are okay! Add the chocolate chips and stir once or twice until incorporated.
Spray a 24 cup mini muffin tin with cooking spray. Scoop muffin batter into the muffin tins, filling the tins about ¾ of the way full. You should have enough batter for 24-28 mini muffins.
Bake muffins 12-14 minutes at 375ºF. Check that muffins are finished baking by inserting a toothpick into the center of one and making sure it comes out clean (there may be some melted chocolate). Pull muffins out of the oven and let rest for about 5 minutes in the pan before removing to a cooling rack to cool and enjoy!These mini muffins freeze well in an air-tight ziplock bag or container. Reheat in the micrwaove for 10-20 seconds or thaw on the countertop before enjoying.
