

These pictures are rather similar, but I couldn't choose between them.
This is a decadent recipe from Dorie Greenspan. The key is to let the brownies reach room temperature before you eat them- otherwise the ganache will be hard to bite through and the peanut butter frosting will pull away from the brownie.
They are ridiculously decadent.
Peanut Butter Brownies
reposted from epicurious.com
Brownies
3/4 cup (1 1/2 sticks) unsalted butter
7 ounces bittersweet or semisweet chocolate, chopped
3 ounces unsweetened chocolate, chopped
1 1/2 cups sugar
1 1/2 teaspoons vanilla extract
1/4 teaspoon salt
4 large eggs
1 cup all purpose flour
1 cup roasted salted peanuts, coarsely chopped
Frosting and ganache
1 cup chunky peanut butter (do not use natural or old-fashioned)
1/2 cup (1 stick) unsalted butter, divided, room temperature
3/4 cup powdered sugar
1/8 teaspoon salt
1/8 teaspoon ground nutmeg
1 tablespoon whole milk
1 teaspoon vanilla extract
7 ounces bittersweet or semisweet chocolate, chopped
For brownies:
Position rack in center of oven and preheat to 325°F. Line 13x9x2-inch metal baking pan with foil, leaving long overhang; butter foil.
Place 3/4 cup butter in heavy large saucepan. Add both chocolates; stir over low heat until smooth. Remove from heat. Whisk in sugar, vanilla, and salt, then eggs, 1 at a time. Fold in flour, then nuts. Spread in prepared pan. Bake until tester inserted into center comes out with moist crumbs attached, about 30 minutes. Place pan on rack; cool.
For frosting and ganache:
Using electric mixer, beat peanut butter and 1/4 cup butter in medium bowl to blend. Beat in powdered sugar, salt, and nutmeg, then milk and vanilla. Spread frosting over brownies.
Stir chocolate and 1/4 cup butter in heavy small saucepan over low heat until smooth. Drop ganache all over frosting; spread to cover. Chill until set, about 1 1/2 hours. Do ahead Can be made 1 day ahead. Cover and keep chilled.
Using foil as aid, transfer brownie cake to work surface; cut into squares. Bring to room temperature; serve.