Cookie Dough: Using an electric mixer cream together the butter, brown sugar, granulated sugar and vanilla on medium-high speed. Beat for 2 minutes until fluffy and light beige in color.
Add the eggs one at a time beating well after each addition. Stop and scrape sides of the bowl periodically.
In a medium-size mixing bowl use a whisk to sift together the flour, pudding mix, cocoa powder, baking powder, baking soda and salt.
Lower to medium speed and gradually add the flour mixture to the wet ingredients. Once all is added beat for 15-30 seconds or just until fully incorporated.
Fold in the chocolate chunks by hand until evenly distributed in the dough.
Place into an airtight container and chill for 30-60 minutes.
Bake: Preheat the oven to 375°F. Line 2 cookie sheets with parchment paper or a silicone mat.
Roll the cookie dough in 1 1/2-inch balls. Arrange cookie dough balls on the prepared pan leaving at least 2-inches between each. Using the palm of your hand flatten the centers.
Bake for 10-12 minutes. Cool on the baking sheet for 2-3 minutes then remove to a wire rack to cool completely.
Store in an airtight container at room temperature for up to 3 days.