01 -
Place the chocolate in a heatproof bowl. Heat the cream until steaming, pour it over the chocolate, add the butter, and let stand for 2 minutes. Stir until smooth.
02 -
Chill the ganache until firm enough to scoop, about 30 minutes. Divide into 6 mounds, roll quickly into balls, and freeze until solid, at least 45 minutes.
03 -
Heat the oven to 350°F. Grease a 6-cup jumbo muffin tin very well and dust lightly with cocoa powder, tapping out the excess.
04 -
Melt the butter, semi-sweet chocolate, and unsweetened chocolate together gently in a microwave or over a double boiler. Stir smooth and cool for 5 minutes.
05 -
Whisk the sugar, eggs, egg yolk, vanilla, and salt until smooth and slightly lighter. Whisk in the melted chocolate mixture, then fold in the flour and cocoa just until combined.
06 -
Spoon enough batter into each muffin cup to cover the bottom. Press one frozen ganache ball into each cup, then cover completely with the remaining batter.
07 -
Bake for 16-18 minutes, until the edges are set and the tops are puffed but still soft in the center. Do not overbake or the filling will thicken.
08 -
Cool in the pan for 5 minutes. Run a thin knife around each brownie, turn out carefully, and serve warm with raspberries, powdered sugar, or ice cream.