- 2 cups bittersweet chocolate chips (or chopped bittersweet chocolate), divided into 1 1/2 cups and 1/2 cup
- 2 tablespoons unsalted butter
- 2 eggs
- 1/2 cup sugar
- 1 teaspoon vanilla
- 1/4 cup all-purpose flour
- 1/4 teaspoon baking powder
- 1/4 teaspoon salt
- 1/2 teaspoon espresso powder (optional, for enhanced chocolate flavor)
- 3 tablespoons flaky sea salt
- In a double boiler, melt together 1 1/2 cups of the chocolate with the butter. Set aside.
- Beat together the eggs and sugar until pale and fluffy, about 2 minutes. Slowly add the warm chocolate mixture, beating as you add.
- Add the vanilla to the egg/chocolate mixture and mix well.
- Add the flour, baking powder, salt, and espresso powder (if using) and mix thoroughly.
- Add the remaining 1/2 cup of chocolate (if the batter is still rather warm from the chocolate, let it cool until it's warm but not hot before adding the chocolate so that it doesn't melt the additional chocolate), and stir to combine.
- Chill the batter for 10-15 minutes, while you preheat the oven to 350°F.
- Using a spoon or scoop, scoop heaping tablespoonfuls of the batter onto parchment-lined baking sheets. Sprinkle liberally with flaky sea salt, and bake for 7-8 minutes. Remove the cookies as soon as they start to look dry on the top and develop cracks—do not overbake!! They will still look a bit too soft; that's okay.
- Remove from the oven and let cool.