Position a rack in the center of the oven and preheat to 350 degrees F. Line two baking sheets with baking parchment.
In the top part of a double boiler, over hot, not simmering, water, melt the butter with the unsweetened chocolate and 2 ounces of the bittersweet chocolate. Remove from heat, and let stand until tepid, about 10 minutes.
In a medium bowl, using a hand-held mixer set at high speed, beat the eggs and sugar for about 2 minutes, until light and foamy. Beat in the vanilla and chocolate mixture, just until blended. Stir in 1 cup of the flour, baking powder and salt.
In a small bowl, toss the chocolate chips in the remaining flour. Stir in the remaining bittersweet chocolate and chocolate chips.
Drop by rounded tablespoon, 1 inch apart, on the prepared baking sheets for a super-fudgy, flattish cookie, or refrigerate the dough for a couple hours for a puffier version with less spread.
Bake the cookies for 10 to 12 miunutes or until they’re slightly cracked and still shiny on the outside, soft and gooey inside, and really ugly.