Yields a 2x8”2”/20x5cm Ø cake ring. Make a day ahead. Melt butter and chocolate over water bath stirring every so often. Once just melted remove from the heat and set aside. Meanwhile, beat eggs and sugar on medium high. Pour in chocolate mixture and sift over the flour and baking powder. Mix until just combined. Fill greased mold lined with parchment paper. Fill mold about half way and bake at 375ºF/190ºC for about 15 min; do not over bake. Let cool and freeze.
Barely melt chocolate first. Pour in hot half & half and mix to smooth. Set aside.
Soak gelatin in cold water to soften and drain. Whip chilled heavy cream to soft peaks and keep refrigerated. Melt chocolate to 122ºF/50ºC max. Make a creme Anglaise first: On the stove, warm up milk, vanilla, and sugar to 113/115ºF(45/50ºC). Whisk in yolks and blend well. Cook mixture to 185ºF/85ºC. Remove from heat and whisk in the softened gelatin and sieve over the melted chocolate – whisk well and let the chocolate mixture to cool down to 105ºF/40ºC. Fold in one-third of the whipped cream, then add remaining whipped cream. Use immediately.
Remove brownie from the mold. Peel off parchment and insert brownie inside the cake ring. Use an acetate cake collar or parchment to ease unmolding. Split ganache in half and spread over each brownie and add the chocolate mousse. Freeze Lisbon chocolate for at least 4 hours to set. Lightly blow torch frozen cake ring if not using acetate cake collar to ease removal. Place cake on a flat tray or large plate. Place in the refrigerator to thaw. Dust unsweetened cocoa powder. Leave cake at room temperature for about 30 minutes before serving. Enjoy!