First, preheat your oven to 220°C (425°F). Line a muffin tin with paper liners or lightly grease the cups to prevent sticking.
In a large mixing bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt until evenly combined and lump-free.
Gradually pour the wet ingredients into the dry ingredients and gently fold together until just combined. Be careful not to overmix, as this helps keep the muffins soft and fluffy.
Next, gently fold in the chocolate chips or chocolate chunks for extra gooey texture and rich chocolate flavour.
For taller bakery-style muffin tops, let the batter rest for 20–30 minutes before baking. This step helps hydrate the flour and improves the rise.
Spoon the batter into the prepared muffin tin, filling each cup about ¾ full. Top with extra chocolate chips if desired for a bakery-style appearance.
Bake the muffins at 220°C (425°F) for 5–7 minutes to create a strong initial rise. Then reduce the oven temperature to 175°C (350°F) and continue baking for another 10–15 minutes until a toothpick inserted comes out with moist crumbs.
Let the muffins cool in the pan for 5–10 minutes before transferring them to a wire rack to cool completely.