This combination brownie/cookie is the reason milk was invented.
1/2 cup unsalted butter
4 ounces unsweetened chocolate, chopped
1 cup brown sugar
2 tablespoons granulated sugar
2 large eggs
1 teaspoon vanilla extract
1/2 teaspoon baking soda
1/2 teaspoon fine sea or table salt
1/2 cup unsweetened cocoa powder, any kind will work
1 cup all-purpose flour
2/3 cup chocolate chips or bitter- or semisweet chocolate, chopped into chunks
Melt butter and unsweetened chocolate together until almost melted. Stir until smooth.
Whisk sugars into melted butter and chocolate, then eggs, one at a time, then vanilla.
Whisk in baking soda and salt. Add cocoa powder and flour. Stir until just combined.
Add chips or chocolate chunks and stir until combined.
Place bowl in the fridge for about 30 minutes up to a few days.
Heat oven to 350°F.
Scoop into about 1 1/2- to 2-tablespoon sized mounds and space evenly on parchment- or nonstick baking mat-lined baking sheets, allowing room for them to spread a little.
Bake for 11 to 12 minutes, at which point they will still definitely look underbaked, but you should take them out if a fudgy-centered cookie is your goal. And why wouldn’t it be?
Let set on baking sheets for a few minutes before carefully transferring to a rack to cool if you can wait that long.
I got the recipe here.