Preheat oven to 400°F . Add liners to a 12-muffin baking pan.
In a large bowl, mix the first 7 ingredients (dry ingredients).
In a separate bowl mix the wet ingredients: egg, buttermilk, orange juice, oil, and vanilla.
Add the wet ingredients to the dry ingredients. Mix only until everything's blended, but don't overmix.
Add the chocolate chips and mix.
Spoon batter into the liners. Fill each approximately 2/3 full. Make sure the batter is evenly distributed among the 12 liners, to ensure all the muffins will bake the same.
Bake for 20 minutes, or until toothpick inserted into the center of a muffin comes out clean. Cool for five minutes. Enjoy!
Notes
To make a chia seed egg replacement:Mix 1 tbsp chia seeds with ⅓ cup water. Let stand for 5 minutes before using in the recipe. Grinding the chia seeds first is optional; I usually skip that step.Regarding the batter:When you mix the wet and dry ingredients together, the mixture will seem a bit dry and lumpy. You'll be tempted to add more milk to smooth it out, but don't do it. Regarding the yield:This recipe will yield 12 regular-sized muffins, not jumbo muffins. If you're making jumbo muffins, your yield and baking time will vary.