In a large bowl, whisk together the all-purpose flour, granulated sugar, baking powder, baking soda, salt, and 1 cup of the mini chocolate chips until combined. In a separate bowl, vigorously whisk the eggs with the sour cream until a smooth mixture forms. Blend in the vanilla extract, pure maple syrup, and vegetable oil, followed by the melted butter, then finally the buttermilk. Gradually pour the wet ingredients into the dry ingredients, gently folding the mixture just until no dry streaks remain, being cautious not to overmix. Cover the bowl with plastic wrap and allow it to rest at room temperature for one hour to activate the leaveners, promoting a higher muffin crown; if pressed for time, the batter can be baked immediately with slightly less height. Once rested, preheat the oven to 425°F and prepare a muffin tin with 12 paper liners. Using an ice cream scoop, carefully scoop the airy batter into each liner, slightly overfilling each. Distribute a generous sprinkle of coarse sugar and an ample mound of mini chocolate chips over the tops of each portion. Bake at 425°F for 8 minutes, then, without opening the oven door, decrease the temperature to 350°F and continue baking for an additional 8-10 minutes. Insert a toothpick into the center of a muffin to check for doneness, avoiding a prolonged opening of the oven door. Remove the muffins and allow them to cool in the pan for 10 minutes before gently loosening them with a knife if necessary and transferring to a wire rack. Let cool for another 10–15 minutes before serving warm.