01 - Preheat oven to 350°F. Grease and line an 8-inch square baking pan with parchment paper.
02 - In a saucepan, melt 4 oz butter over low heat. Remove from heat and stir in sugar, eggs, and vanilla until smooth.
03 - Sift flour, cocoa powder, and salt into the wet mixture. Stir until just combined, being careful not to overmix.
04 - Spread batter evenly in prepared pan. Bake for 20 to 25 minutes until a toothpick inserted in the center comes out with moist crumbs. Cool completely in the pan before cutting.
05 - Combine heavy cream, chocolate chips, sugar, and butter in a small saucepan over medium heat. Stir constantly until smooth and glossy, approximately 3 to 4 minutes. Remove from heat and stir in vanilla and salt.
06 - Cut cooled brownies into squares. Place one brownie square in each serving bowl.
07 - Top each brownie with a generous scoop of vanilla ice cream.
08 - Drizzle hot fudge sauce over the ice cream. Add whipped cream, nuts, and a cherry if desired. Serve immediately.