Preheat oven to 350F.
Add 6 oz chocolate and 1/3 cup stout beer to the top of a double boiler, stir until melted, remove from heat.
In a large bowl stir together the melted butter and both kinds of sugar. Stir in the eggs.
Stir in the chocolate and beer.
Add the flour, cocoa powder and salt, stir until just combined.
Line an 8x8 pan with parchment paper. Pour batter into prepared pan.
Bake at 350F for 28-30 minutes or until the top is slightly firm and the batter no longer jiggles when the pan is shaken. Remove from oven, allow to cool completely, at least one hour. Brownies are best made a day ahead of time.
Remove the brownies from the pan using the parchment paper.
Cut into four squares.
Add the remaining 10 wt oz dark chocolate to the top of a double boiler along with the remaining 1/3 cup stout. Stir until melted, remove from heat. Can be made a day ahead of time. Store in an airtight container in the refrigerator, reheat slightly before using.
Plate one brownie, top with ice cream, then another brownie, then another scoop of ice cream. Drizzle with chocolate sauce, sprinkle with chocolate chips if desired.