Marcus Cookies

Equipment:

Electric hand mixer, at least 200 watts.
Very large mixing bowl, about 18 inches across by 8 inches deep, or about 12 quarts.
Measuring cups and spoons.
Parchment paper.
Cookie sheets. One batch will fill about three 18x26 inch cookie sheets, making about 90 cookies.
Mixing spoon.
Ice cream scoop.
Oven.

Ingredients:

1 pound unsalted butter. It helps the texture if it's more than 80% butterfat. Strauss European Style, Challenge European Style, and Plugra all work.
1 pound (or about 2 compressed cups) dark brown sugar. This is equal to 1 of C&H's small boxes.
1.5 cups white sugar.
1 ounce (2 tablespoons) vanilla extract. Cook's Cookie Vanilla may help a bit, but it's expensive.
3 large eggs.
2 pounds (6 cups) white flour. I like Italian "Tipo 00" flour. The most widely available type is "Antimo Caputo", in a red bag. It's meant for pizza, but I've been pleased with the results. The bag is slightly more than 2 pounds -- I usually just dump it in, holding back a handful or so.
1.5 teaspoons baking soda.
1.5 teaspoons regular salt. Or, instead, 0.5 teaspoons regular salt, and a few pinches of coarse salt flakes as topping.
6 ounces (1.5 cups) cacao nibs.
12 ounces (2 cups) dark chocolate chips. I like Guittard's "Akoma" chips for this.
12 ounces (2 cups) milk chocolate chips. I like Ghirardelli for this.

Note that almost all of the ingredients can be found at Piazza's, except cacao nibs, which can be found at Whole Foods.

Directions:

Pre-heat the oven to 350 degrees.
Let the butter sit out until it's room temperature (several hours). Or, microwave it at low power until it's close to melting.
Put the butter, dark brown sugar, and white sugar in the mixing bowl. Mix them together with the electric hand mixer, making sure to break up any clumps of brown sugar. Continue mixing until the ingredients are well mixed, and the spires of dough have slightly jagged edges.
Beat in the vanilla.
Add the eggs one at a time, beating thoroughly after each one, for a total of about 3 minutes.
Add the flour, baking soda and regular salt (not the salt flakes, if you're using that). Mix just until the flour has disappeared, and no longer than that. This should take less than 30 seconds.
Add the chocolate chips and cacao nibs. Mix them in well with the mixing spoon.
Line the cookie sheets with the parchment paper. Drop the dough by ice cream scoop onto the cookie sheets. Don't flatten the dough.
Optionally, put small pinches of salt flakes on each cookie. It may be necessary to grind the flakes a bit with your fingers, if the flakes are too large.
Depending on the oven, bake until the edges of the cookies are just beginning to turn brown, or until they're just about to start turning brown (which takes experience with that oven). In my experience, it takes about 3 minutes longer to bake an 18x26 cookie sheet as it takes to fill the next one. Not overbaking is key. They'll seem underdone and doughy, but they'll firm up as they cool off. If you're re-using the cookie sheets, let the cookies cool at least 10 minutes before taking them off. Don't re-use the parchment paper.

Here's a picture of the original recipe. It got its name because whoever wrote it down thought it tasted like the Mrs. Field's recipe, though IMO this is way off (at least, compared to modern Mrs. Field's cookies). The paper was probably written in the early '80s: