In a large bowl, eg stand mixer, combine margarine, sugars, vanilla and eggs. Mix thoroughly - about 4 minutes - until thoroughly blended.
Sift together chocolate pudding, cocoa powder,flour, baking soda and salt.
Add sifted dry ingredients to margarine mixture. Combine until incorporated - about 1 minute. Work quickly once dry ingredients added because pudding mix may make it harder to mix.
Mix in chocolate chips and chopped dark chocolate to combine.
Using small ice cream scoop or two tablespoons, form approximately 24-27 balls of dough. Place on a plate, cover with plastic wrap and refrigerate 30 minutes.
Preheat oven to 350 degrees F. Prepare 3 baking sheets lined with parchment paper or Silpat, or lightly spray cookie sheets.
Remove chilled cookie dough from fridge. Place 8 or 9 cookies per sheet, approximate 2 inches apart. Flatten ever so slightly with back of spoon. Bake for approximately 10 minutes or until edges just begin to brown. Cookies will appear uncooked on top, but allow to cool 10 minutes on cookie sheet and they will set up.
Store cooled cookies in a covered container or sealed plastic bag.
NB. The original recipe called for butter instead of margarine, but I found it spread too much unless chilled for several hours. When it comes to chocolate cookies, no one wants to wait that long! :0)