Combine the 2 Tbsp flour, 2 Tbsp brown sugar and salt in a small bowl.

Cut the butter into the mixture using knives or your hands until the mixture is crumbly.

Add the hazelnuts and set aside.

Preheat the oven to 350 degrees.

Combine the flour, salt and baking powder in a bowl and set it to the side.

In another bowl, cream together the sugar and butter until it is light and fluffy.

Add in the eggs, one at a time and mix.

Add the vanilla and mix.

Take ½ of the flour mix and add to the batter and combine.

Add ½ of the milk and combine.

Repeat until both the flour and milk have been incorporated into the batter and everything is thoroughly mixed.

In a small bowl mix together the nutella, cocoa powder, hazelnuts and warm water and stir to combine.

Divide the flour/sugar batter evenly between 2 bowls and into one, add the nutella/chocolate mix and stir.

Using a cookie scoop, place alternating scoops of chocolate and vanilla batter into a 9” x 5” baking pan that has been well greased, or use a nonstick option.

Using a knife, draw back and forth through the dough lengthwise to swirl the doughs together.

Place in the oven and bake for 40 minutes.

Remove and add streusel topping.

Return to the oven and bake for another 10 minutes.

Add a piece of foil to the top to prevent the streusel from burning and bake the remaining 10 minutes, or until a knife comes out clean.

Allow to rest in the pan for about 5 minutes, before removing and allowing to cool completely on a rack.