Pre-heat the oven to 350 F degrees. Line a baking tray with parchment paper or cover it with some non-stick spray and set aside.
Sift together flour, cornstarch, salt and baking soda in a bowl, set aside.
In steel bowl of your stand mixer fitted with paddle attachment or using your hand mixer cream together butter and both sugars till smooth and creamy, around 2-3 minutes. Add vanilla, water and mix.
Add the flour into the butter-sugar mixture.
Stir in the tutti frutti and mix till to form a dough.
Make the filling by creaming together softened butter and sugar. Add cocoa powder and mix till you have smooth consistency filling ready.
To make the cookies take 1 tbsp of dough, flatten it slightly and then using your thumb make a depression in the center. Fill the center with little chocolate filling. Then take 1 tbsp of dough again, flatten it a bit and put it over the chocolate filled dough. Seal the edges, then using your hands roll it to form a round shape and then flatten it slightly.
Place the cookies on to the baking tray leaving 2 inch space between each cookie.
Bake at 350 F degrees for 13-15 minutes.
Transfer on wire rack to cool completely.
melt chocolate chips in the microwave, stir after every 15 seconds so that the chocolate doesn't seize and form a lump. Add 1/2 teaspoon of shortening if the mixture isn't smooth. Drizzle over cookies once completely cooled.