Ingredients

Brownies:

2 sticks (16 tbs) unsalted butter, cut into pieces
6 oz finely chopped unsweetened chocolate
2 cups sugar
1 1/2 tbs. espresso powder
2 tsp. vanilla
1/4 tsp. salt
3 large eggs
1 cup all-purpose flour

Glaze:

1/4 cup plus 2 tbs. water
3 tbs. unsalted butter
6 oz finely chopped bittersweet chocolate
Garnish: chocolate-covered espresso beans (optional)
Equipment: a 13- by 9- by 2-inch baking pan

Directions

To Make brownies: Preheat oven to 350F with rack in middle. Line baking pan with foil, leaving a 2-inch overhang on short sides, then butter foil.
Melt butter and chocolate in a medium metal bowl set over a pan of barely simmering water, stirring until smooth. Remove bowl from pan, then stir in sugar, espresso powder, vanilla,& salt with a large spoon. Add eggs, one at a time, stirring until smooth and mixture leaves side of bowl. Add flour and stir until just combined.
Transfer batter to pan and bake until a tester inserted into center comes out with some crumbs adhering, 20 to 25 minutes. (Do not overbake.) Cool in pan on a rack 30 minutes.
To Make glaze: Meanwhile, combine all glaze ingredients in a metal bowl, then set over a pan of barely simmering water and heat, stirring, just until smooth. Remove from pan, then pour glaze over pan of warm brownies and spread evenly with a small offset spatula. Let stand at room temperature until glaze is set, about 3 hours. Remove brownies from pan using foil as an aid and cut into 1-inch bites with a thin blade knife, cleaning knife as necessary to maintain a clean edge. Garnish with espresso beans.
* Brownie layer can be made 3 days ahead (without glaze) and kept chilled in 1 piece wrapped well in foil. Bring to room temperature before glazing, about 2 hours. Glazed and cut brownie bites can be made 1 day ahead and kept, loosely covered, at room temperature.