Preheat oven to 350 degrees F.
Put melted margarine in large bowl. Stir in sugar and vanilla. Beat in eggs one at a time.
Add cocoa and beat until blended. Don't worry if you get too much cocoa. Add flour, baking powder, and salt, and beat well.
Stir in chocolate chips. Try not to eat too many now -- that's what the other half of the package is for.
Pour batter into greased 9"x13" baking pan. Bake 30-35 min at 350 degrees F.
Lick the bowl while you're waiting....
Let cool, and cut however you want. Makes 117 square inches of brownie.