Line the outside of a springform pan with aluminum foil and crimp at the top of the pan. (This is necessary to prevent the batter from leaking out of the pan while it's baking.) Spray the inside of the pan with non-stick spray. Preheat oven to 350 degrees.
Melt butter and chocolate in double boiler over medium-low heat, stirring occasionally. Stir in vanilla and pinch of sea salt. Remove from heat and allow to cool to room temperature.
Beat eggs and sugar at low speed until combined. Then beat at high speed for 8-10 minutes, until the mixture is pale yellow and leaves a trailing taffy-like ribbon when the beaters are removed.
Fold 1/3 of egg mixture into room temperature chocolate mixture. Then fold in remaining egg mixture.
Spoon batter into greased springform pan. Bake for 50-55 minutes or until the center is firm and a toothpick comes out with moist crumbs attached. Let cool completely and then release the springform and put the cake on a cake plate.
Heat cream for ganache until bubbles form at the edges. Pour over chocolate and let sit for 5 minutes. Whisk until well combined. Add vanilla and sea salt and whisk until smooth. Pour over cooled cake, making sure to drizzle the ganache over the edges of the cake. Garnish with berries or sliced almonds. Cover and refrigerate for several hours (or overnight) until firm.
Use a sharp knife to cut and clean the knife between each slice. Serve with amaretto-infused whipped cream.