• Preheat the oven to 350° F then spray and line a 9 inch springform pan with parchment paper.
• In a medium size microwavable safe bowl, melt the 1/2 cup butter and 6 oz chocolate together, 30 seconds at a time until fully melted.
• Add in the 1 cup sugar, 3 eggs, and 1 tsp vanilla. Mix on low to medium speed with a hand mixer or whisk by hand.
• Add in the 2/3rd cup flour, 1 tbsp cocoa, and 1/4 tsp salt. Mix until combined.
• Pour the batter into the prepared pan and bake for 25-28 mins until the center is no longer jiggly. Cool.

Make the mousse

• Melt the 2 tbsp butter and 8 oz chocolate together in a large microwave safe bowl (glass preferred) for 30 seconds at a time, mixing in between until the chocolate is completely melted. Cool. Combine the 1/2 tablespoon of instant coffee with hot water in a cup. Pour it into the chocolate and mix.
• Separate the eggs by adding the whites into the mixing bowl of a stand or hand mixer, and the yolks into the chocolate mixture. Mix the chocolate mixture with a spatula until combined. It will get a bit thicker, thats ok!
• Using the whisk attachment whip the egg whites on high speed, pouring in the 1/4 cups sugar slowly while whipping. Continue whipping until stiff peaks form. You know the whites are ready when you take the beater out, flip it upside down and the tip of the egg white can hold itself up.
• Fold 1/2 of the egg whites into the chocolate mixture at a time making sure not to deflate them. Fold until there are no white streaks left then continue until there are no more egg whites.
• Lightly wash out your mixing bowl and beater. Add 1 cup cold heavy whipping cream and 1/4 tsp cream of tartar to the bowl. Beat on high speed until stiff peaks form. About 1 minute. This can happen fast! Make sure you watch it or it can curdle when over mixed.
• Unclasp the springform pan and line acetate or parchment paper around the cake on the inside of the pan until it reaches the bottom. This means the cake has to come off the sides of the pan. Make sure its lined at the bottom or the mousse with seep out. Pour the chocolate mousse on top of the cake. Spread with a spoon to flatten all over evenly.
• Refrigerate the cake for 4 hours or overnight. Add fresh fruit on top before serving, raspberries are a favorite!