Brownies
4 (1 ounce) squares semisweet chocolate
1/2 cup unsalted butter
4 eggs
2 cups granulated sugar
1/4 teaspoon salt
1 cup sifted flour
1 teaspoon vanilla extract
1 cup chopped pecans, divided
6 ounces semisweet chocolate chips
12 large marshmallows

Butter an 8- or 9-inch square baking pan. Set oven rack in the center of the oven and preheat to 350 degrees F.

Melt chocolate and butter in the top of a double boiler over barely simmering water (or microwave, uncovered, on MEDIUM, stirring every 20 to 30 seconds after the first minute, until only a small chunk of chocolate remains). Remove from heat and stir until melted and smooth.

In a bowl, beat together eggs, sugar, salt, flour, vanilla extract and 1/2 cup of the pecans. Add melted chocolate mixture, then transfer batter to the prepared baking pan. Pat chocolate chips and remaining 1/2 cup pecans on top. Bake for 40 minutes.

Meanwhile, halve marshmallows and make chocolate sauce. Remove brownies from oven and reduce oven temperature to 325 degrees F.

Place marshmallow halves on top of brownies. Return to oven for 5 minutes, or until marshmallows are slightly browned on top. Pour chocolate sauce over marshmallows and let cool slightly. Swirl sauce lightly into marshmallows, and let set.

Chocolate Sauce
2 (1 ounce) squares unsweetened chocolate
6 tablespoons water
1/2 cup granulated sugar
3 tablespoons butter
1/4 teaspoon vanilla extract

Melt chocolate with water over low heat, stirring until smooth. Add sugar. Cook, stirring, until smooth and slightly thickened. Stir in butter and vanilla extract.