Grease an 8 by 8 inch casserole dish with butter. Sprinkle the inside of the dish with 1 tablespoon of sweetener.
Place the salted butter into a large pot over high heat while whisking often. After a few minutes the butter with froth up and brown flecks will appear. Keep heating until you have a deep golden brown color. Remove from heat. Add in all the chopped chocolate and stir until all the chocolate has melted. Set aside.
In another large bowl place the sweeteners, chocolate Equip protein powder, eggs, egg yolks, coconut milk, and beat with an hand mixer until thickened, about 2 minutes.
Fold the warm chocolate mixture into the egg mixture. Place the batter into the prepared dish. Note: At this point, you can either bake or cover and place in the fridge for up to 3 days. Bring to room temperature and remove the covering before baking.
To bake the cake: Preheat the oven to 350°F. Bake the cake until the edges are puffed and slightly cracked but the center, about 15-20 minutes. (You want the center slightly underdone.)
To make the hot fudge, place the heavy cream, sweeteners in a medium pot over high heat. Once hot, remove from the heat and add the Equip chocolate and chopped chocolate. Stir until chocolate is melted. Stir in the vanilla and salt. Taste and adjust sweetness to your liking. Set in fridge to cool for a 15-30 minutes.
To serve, scoop the warm cake into serving dishes with a large spoon. Top with vanilla protein ice cream, if desired, and a drizzle of hot fudge.