Preheat the oven to 180 degrees Celsius (350 degrees Fahrenheit).
Grease 1 9" or 22 cm square cake tin.
Pour the powdered mixture into a bowl, add the chocolate chips, chopped walnuts, ½ cup of oil and mix.
Stir in 1 cup and 2 tablespoons of warm water in 3 stages, continue mixing until smooth, then add the baking powder (included in the package).
Place the dough in the mould.
Bake for 20 to 25 minutes. Remember that you added chocolate chips to the batter.
Remove from the oven and leave to rest on a wire rack for 10 minutes.
Carefully remove from the mould and leave to cool completely on a wire rack.
Cut into desired portions (9 portions for large portions or 16 portions for small bites).