Preheat oven to 425°F/220°C. Grease 12 muffin cups or line them with liner papers.
In a large bowl whisk together flour, sugar, baking powder, and salt.
In a medium bowl whisk the egg, buttermilk/milk, oil and vanilla extract, and whisk until combined. Pour the egg mixture into the flour mixture and fold with a wooden spoon or a rubber spatula just until combined. Do not overmix. The batter should be thick and lumpy. Fold in chocolate chips.
Divide the mixture between the muffin cups almost all the way to the top. Bake for 3 minutes, then reduce the oven temperature to 375°F/190°C and continue to bake for an additional 12-17 minutes (for standard size muffins; see the above post notes for jumbo and mini muffin baking times) until a toothpick inserted into the center of the muffin comes out clean. If the muffin tops start to brown too fast on the outside but are not fully baked yet, cover the pan loosely with aluminum foil. Overbaking will make the muffins dry so keep an eye on them. Remove from oven and allow to cool for 10 minutes in pan, then transfer muffins to a wire rack to cool completely.
-Both milk and buttermilk taste great but buttermilk makes the muffins much more moist.
- Using chocolate chips or chunks (cut from a chocolate bar) yield a slightly different muffin. Chocolate chips hold their shape well during baking while chocolate chunks (which I cut to different size pieces for varying chocolate texture) are melty and soft. I highly recommend trying both options!
- Muffins are best the same day they are made.
- Muffins can be frozen for up to 2 months, then thawed overnight in the fridge or a couple of hours at room temperature.