PreparationFor Sauce: Bring whipping cream to simmer in heavy medium saucepan. Reduce heat to low. Add chopped milk chocolate and whisk until melted and smooth. Whisk in peanut butter. (Sauce can be prepared 1 day ahead. Cover and refrigerate. Bring to simmer before using, whisking constantly.) For Brownies: Position rack in lowest third of oven and preheat to 350°F. Line 9-inch-high sides with foil, overlapping sides. Butter and flour foil. Melt unsalted butter and chopped unsweetened chocolate in heavy medium saucepan over low heat, stirring constantly. Pour into large bowl and cool slightly. Whisk in sugar and eggs. Stir in flour, then chopped bittersweet chocolate and unsalted peanuts. Transfer batter to prepared pan; smooth top. Bake until tester inserted into center comes out with some moist crumbs still attached, about 45 minutes. Cool at least 1 hour. (Brownies can be made 8 hours ahead. Cool completely. Cover and store at room temperature.) Using foil sides as aid, lift brownies from pan. Fold down foil sides. Cut into squares or triangles. Transfer brownies to plates. Place scoop of ice cream next to each brownie. Spoon warm sauce around brownies and serve immediately.
PreparationFor Sauce: Bring whipping cream to simmer in heavy medium saucepan. Reduce heat to low. Add chopped milk chocolate and whisk until melted and smooth. Whisk in peanut butter. (Sauce can be prepared 1 day ahead. Cover and refrigerate. Bring to simmer before using, whisking constantly.) For Brownies: Position rack in lowest third of oven and preheat to 350°F. Line 9-inch-high sides with foil, overlapping sides. Butter and flour foil. Melt unsalted butter and chopped unsweetened chocolate in heavy medium saucepan over low heat, stirring constantly. Pour into large bowl and cool slightly. Whisk in sugar and eggs. Stir in flour, then chopped bittersweet chocolate and unsalted peanuts. Transfer batter to prepared pan; smooth top. Bake until tester inserted into center comes out with some moist crumbs still attached, about 45 minutes. Cool at least 1 hour. (Brownies can be made 8 hours ahead. Cool completely. Cover and store at room temperature.) Using foil sides as aid, lift brownies from pan. Fold down foil sides. Cut into squares or triangles. Transfer brownies to plates. Place scoop of ice cream next to each brownie. Spoon warm sauce around brownies and serve immediately.