Line a baking sheet with parchment paper. Using a tablespoon, scoop out 8 tablespoons of Nutella onto the prepared baking sheet. Freeze until solid, at least one hour.

In a large mixing bowl add brown sugar, white sugar, vanilla paste, yogurt and melted butter. (I forgot to melt butter so did later but you don't forget)

Mix it thoroughly. It will become pouring consistency.

Sift the dry ingredients all-purpose flour, baking soda, salt and unsweetened cocoa powder together.

Start mixing by adding dry ingredients to wet mixture. Do not add all in one go, add in 3 batches.

Mix it by cut and fold method until it is fully incorporated.

It will form thick, little firm and sticky dough.

Add chopped chocolate or chocolate chips and mix.

Divide the dough into 16 equal pieces and roll them into ball shape. Then flatten them.

Using your thumb, make deep impression in centre of a dough ball. Then take out the Nutella scoops out of the freezer. We have to work quickly at this time else Nutella scoops will start melting. Peel the Nutella scoops from the baking sheet and place them in the middle of the dough Place a flat cookie dough and seal the cookie.

Press and shape it round.

Prepare all cookies like these. Cover the cookies with a plastic wrap and freeze for at least 1 hour.

Answer - Chilling cookie dough before baking solidifies the fat in the cookies. As the cookies bake, the fat in the chilled cookie dough takes longer to melt than room-temperature fat. The longer the fat remains solid, the less cookies spread. Also chilling enhances flavours and texture.

Preheat oven at 350 Fahrenheit or 172 degree Celsius and set the rack in middle position of oven. Line a baking sheet in a baking tray and place cookies 2 inch apart. Bake for 11 minutes. The cookie should not be sticky and shiny. The centre will be soft to touch, don't worry they continue to cook after they come out from the residual heat.