Brownie: 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
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: Melt chocolate with water over low heat, stirring until smooth.
Add sugar. Cook, stirring, until smooth and slightly thickened.