Preparation

1. Preheat the oven to 220℃.  Line the muffin pan with tulip muffin liners.
2. In a medium mixing bowl, add all purpose flour, baking powder, baking soda and salt. Mix them well with a whisk. Set it aside.
3. In another medium mixing bowl, mix 1 cup chocolate chips and 1/2 cup hazelnut. Spray them with water and mix well.
4. Add in 2 tbsp all purpose flour. Mix until all the chips and hazelnuts are well coated with flour. Set it aside.

For the muffin batter

1. Mix the oil and milk in a medium mixing bowl using a whisk until they are emulsified.
2. Add in eggs and vanilla extract. Mix well.
3. Swirl in the sour cream until just combined followed by caster sugar and light brown sugar. Whisk the mixture until everything is well incorporated.
4. Place a sift on top of the mixing bowl, sift the dry ingredient mixture into the wet mixture. Mix gently using a spatula until just combined.
5. Fold in the flour coated chopped hazelnuts and chocolate chips until just evenly distributed throughout the batter.
6. Scoop the batter evenly into each muffin liner using an ice cream scoop. Fill each most of the way to the top.
7. Distribute the remaining chocolate chips and chopped hazelnuts over the top of the muffin batter.
8. Bake the muffins for 5 minutes at 220℃. Then reduce the oven temperature to 180℃, continue to bake them for further 13 – 15 minutes or until a toothpick inserted in the centre comes out clean.
9. When the muffins are done, remove them from the oven immediately and allow the muffins to cool in the muffin pan for 5 minutes.
10. When they are still warm and you can comfortably handle them, transfer them to a wire rack to cool completely.
11. Enjoy with a cup of coffee or any of your favourite drinks!