Step by step

1. Place flour, baking powder, sugar, salt and vanilla extract in a bowl of a stand mixer fitted with Flat Beater.

2. Mix for 30 seconds on stir speed.

3. Place a new bowl in the stand mixer and add sunflower oil, milk, melted butter, eggs and sour cream into it. Mix on speed 2 for 1 minute.

4. Add the wet ingredients to the dry ingredients and mix on speed 2 until just combined.

5. Place chocolate in a blender and let it run on speed 1 until chocolate is chopped.

6. Add the chocolate to the muffin batter. Mix on speed 1 until just combined.

7. Line a 12-count muffin pan with cupcake liners.

8. Divide batter among prepared muffin pan, filling almost all the way to the top.

9. Bake in a 180°C preheated oven for 25-30 minutes until the tops are golden brown and centers are set.