Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking pan with cooking spray or line it with parchment paper.

In a large mixing bowl, combine the melted butter and granulated sugar. Mix until well combined.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, cocoa powder, salt, and baking powder. Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Pour the brownie batter into the prepared baking pan, spreading it evenly. Bake for 25-30 minutes or until a toothpick inserted into the center comes out with a few moist crumbs.

Allow the brownies to cool completely in the pan on a wire rack. Once cooled, remove the brownies from the pan if using parchment paper.

Slice the brownies in half horizontally to create two layers. Place one layer back in the pan.

Spread the softened vanilla ice cream evenly over the first brownie layer. Drizzle half of the chocolate fudge sauce over the ice cream.

Place the second brownie layer on top of the ice cream. Drizzle the remaining fudge sauce over the top.

Spread the whipped cream over the fudge sauce, smoothing it out. Garnish with chocolate shavings or sprinkles if desired.

Cover the cake with plastic wrap and freeze for at least 4 hours or until firm.

When ready to serve, remove from the freezer and let it sit for about 10 minutes before slicing.