Preheat oven at 180C or 350F. Also slightly grease a cookie tray. You can also line the tray with parchment paper.
Add soft butter and sugars into a mixing bowl. Also add vanilla. Cream them together until fluffy and light. You can use an electric beater or wired whisk.
Mix wheat flour, cocoa powder and baking powder well in another bowl.
Add the dry ingredients to the creamed butter and mix. You may add 1-2 tablespoons milk or water if the dough is very dry. I did not use either.
Now fold the chocolate chunks to the cookie dough. Chill the dough in refrigerator for 20 minutes.
Scoop out 15 equal balls from the chilled dough. I used 1 tablespoon measuring spoon for uniform size.
Flatten the balls slightly and arrange in the cookie tray. the cookies will spread so leave some space between them.
Bake in the preheated oven for 10-12 minutes.
Remove the cookies from oven when they are slightly soft to touch. They will look under baked and it is the right time to remove them from oven. The cookies will further cook on cooling.
Once the cookies are off the oven, cool them in the cookie sheet for 3-4 minutes. Then remove and cool completely in a wire rack. Store double chocolate cookies in airtight container and serve as required.