In a large saucepan, combine chocolate and butter. Heat over low heat until melted and smooth. Remove from heat.
Beat in eggs, granulated sugar, vanilla and sea salt until thoroughly blended.
Stir in flour, blending well. Spread evenly in bottom of prepared pan.
Bake 25 to 30 minutes. DO NOT OVERBAKE. Cool in pan.
While cooking the fudge, prepare Chocolate Marshmallow Frosting.
When fudge is done, allow to cool, then spread frosting over brownie base. Refrigerate several hours or overnight. Cut chilled brownies into bars. Makes 40 bars.
To Make Chocolate Marshmallow Frosting
In medium saucepan, combine chocolate and butter. Heat over low heat until melted and smooth. Remove from heat.
Add eggs, vanilla, and powdered sugar, beating until smooth. Stir in marshmallows.