2 cups all-purpose flour
1/2 cup Dutch-processed cocoa powder
2 teaspoons baking powder
1 teaspoon table salt
16 ounces semisweet chocolate , chopped
4 large eggs
2 teaspoons vanilla extract
2 teaspoons instant espresso powder
10 tablespoons unsalted butter (1 1/4 sticks), softened but still firm/cool
1 1/2 cups light brown sugar
1/2 cup granulated sugar
2 cups semi-sweet chocolate chips, set aside
1. Sift together flour, cocoa, baking powder, and salt in a medium bowl; set aside.
2. Melt chocolate in a medium heatproof bowl set over pan of barely-simmering water, stirring once or twice, until smooth; remove from heat.
3. Beat eggs and vanilla lightly with fork, sprinkle coffee powder over to dissolve, and set aside.
4. In the bowl of standing mixer fitted with paddle attachment (or with a hand mixer), beat butter at medium speed until smooth and creamy, about 5 seconds (15 seconds with hand mixer). Beat in sugars until combined, about 45 seconds (1 1/2 minutes with hand mixer); mixture will look granular. Reduce speed to low and gradually beat in egg mixture until incorporated, about 45 seconds (1 1/2 minutes with hand mixer).
5. Add chocolate in a steady stream and beat until combined, about 40 seconds (1 minute with hand mixer). Scrape the bottom and sides of the bowl with a rubber spatula. With the mixer at low speed, add the flour mixture and mix until combined, about 40 seconds (1 minute with hand mixer). Do not overbeat. Stir in 2 cups of chocolate chips.
6. Cover with plastic wrap, and let stand at room temperature until consistency is scoopable and fudge-like, about 30 minutes.
7. Meanwhile, adjust oven racks to upper- and lower-middle positions and heat oven to 350 degrees. Line 2 cookie sheets with parchment paper.
8. Leaving about 1 1/2-inches between each ball, scoop dough onto parchment-lined cookie sheets with 1 3/4-inch diameter ice cream scoop.
9. Bake cookies until edges have just begun to set but centers are still very soft, about 10 minutes, turning cookie sheets from front to back and switching from top to bottom racks halfway through baking. Do not overbake! They will look like they are not quite done.
10. Cool cookies on sheets about 10 minutes, slide parchment with cookies onto wire rack and cool to room temperature; remove with wide spatula.