Preheat oven to 325°. Line an 8-inch square baking pan with heavy-duty foil, letting excess extend over sides of pan. Spray foil with cooking spray.
In a small bowl, whisk together flour and salt.
In the top of a double boiler, combine chocolate and butter. Cook over hot but not simmering water, stirring constantly, until melted and smooth. Remove from heat. Add sugar, eggs, and vanilla extract, stirring until incorporated. Add flour mixture, stirring to combine. Pour batter into prepared pan, spreading in an even layer.
Bake until a wooden pick inserted in center comes out with a few moist crumbs, 25 to 27 minutes. Remove from oven, and immediately spread marshmallow crème onto brownie. Sprinkle chocolate chips and almonds over marshmallow crème. Let cool completely in pan.
Cover and refrigerate until very cold, approximately 4 hours.
Using excess foil as handles, remove brownie from pan, and place on a cutting surface. Using a long sharp knife, trim edges from brownie. Cut diagonally into diamond shapes, pressing down (not sawing) with knife. Place in an airtight container, and refrigerate for up to 3 days.
Notes
Kitchen Tip: To ensure brownies have neat, cleanly cut edges, refrigerate them until very cold (at least 4 hours) before cutting, and wipe knife with a warm, damp cloth between cuts.
Recipe by TeaTime Magazine at https://teatimemagazine.com/rocky-road-brownies-recipe/