We prefer semi-sweet dark chocolate for baking. The sweetness of the baked product comes out just right.Substituting milk chocolate will make the brownies too sweet and cloying.But then again, some people find the subtle bitterness of dark chocolate disconcerting. It's up to you whether to make the substitution.
Lightly grease a 7" x 11" pan and line with a sheet of aluminum foil or parchment paper which should be large enough to leave overhangs on all sides to make lifting the cooked baked product easily.
Make the chocolate cookie dough
Whisk together the flour, baking powder and salt.
In a large mixing bowl, beat the butter and sugar until light and fluffy. Add the egg. Beat until smooth.
Add the flour mixture. Mix until smooth. Stir in the chocolate morsels. The cookie dough will be soft but not runny.
Divide the cookie dough into three portions.
Spread two-thirds on the lined baking pan.
Chill the remaining one-third.
Make the brownie mix
Place the chocolate and butter in a large glass mixing bowl. Heat in the microwave, at MEDIUM heat, for three to four minutes or until softened. Alternatively, use a double boiler and melt over hot water. Beat the chocolate and butter until smooth. Cool.
Add the eggs, one at a time, mixing after each addition.
Add the sugar and salt. Mix.
Add the flour and coffee granules. Mix until smooth.
Pour the brownie mix on top of the chocolate cookie dough.
Bake
Take the chilled chocolate cookie dough out of the fridge.
Drop by pinches on top of the brownie mix.
Put the baking pan in the oven and bake for an hour to an hour and a half. Check after an hour for doneness by piercing the center with a toothpick of skewer.
Cool the baked slab completely in the pan (I cooled it overnight at room temperature) before cutting the chocolate chip cookie dough brownies into squares or rectangles.