- 3/4 cup (packed) dark brown sugar
- 1/4 cup lightly packed unsweetened cocoa powder (preferably Dutch-process)
- 5 teaspoons instant espresso powder
- Pinch of salt
- 1 2/3 cups warm water
- 1 1/2 tablespoons vanilla extract
- 1 cup all purpose flour
- 3/4 cup sugar
- 1/4 cup lightly packed unsweetened cocoa powder (preferably Dutch-process)
- 2 teaspoons baking powder
- 1/2 teaspoon salt
- 1/2 cup buttermilk
- 1/4 cup (1/2 stick) unsalted butter, melted
- 3/4 teaspoon vanilla extract
- 1 cup chopped walnuts, toasted
- Whipped cream
- Combine first 4 ingredients in small saucepan. Gradually whisk in 1 2/3 cups warm water and vanilla. Bring to simmer over low heat, whisking often. (Can be made 2 days ahead. Cover and refrigerate. Rewarm over low heat before continuing.)
- Preheat oven to 325°F. Grease 8 x 8 x 2-inch baking pan with shortening. Whisk first 5 ingredients in large bowl to blend. Mix in buttermilk, butter and vanilla, then walnuts (batter will be thick). Spread in prepared pan. Pour syrup over brownie layer.
- Bake brownie until sauce bubbles around sides and brownie layer has risen almost to top of pan and feels firm to touch, about 40 minutes. Transfer to rack and cool 10 minutes.
- Cut dessert into squares. Serve warm, accompanied by whipped cream.