1.Remove seeds from half the muscatels; place in a small bowl. Place remaining muscatels on the vine in another small bowl. Place muscat in a small saucepan over medium heat; bring to the boil. Pour hot muscat equally between the bowls; stand for 30 minutes. Strain seeded muscatels over muscatels on the vine.
2.Preheat oven 160°C/325°F. Grease a 20cm (8-inch) square cake pan; line base and sides with baking paper.
3.Melt butter in a medium saucepan over low heat; stir in chocolate until smooth. Remove from heat; stir in brown sugar. Cool 10 minutes. Whisk eggs into chocolate mixture. Stir in seeded muscatels until coated in mixture, then stir in flours and sour cream. Pour mixture into pan; smooth the surface.
4.Bake cake for 1 hour 10 minutes or until top is firm and a skewer inserted in the centre comes out with moist crumbs attached. Cool in pan.
5.Meanwhile, drain remaining muscatels over a small saucepan; reserve muscatels. Add caster sugar to pan; bring to the boil, stirring until sugar dissolves. Reduce heat; simmer for 5 minutes or until syrup thickens. Add muscatels on the vine; simmer for 1 minute. Cool.
6.Make fudge icing. Place chocolate in a heatproof medium bowl over a medium saucepan of simmer water (don’t allow bowl to touch water); stir until just melted. Add sour cream, then gradually add sifted icing sugar, stirring until smooth.
7.Spread frosting on cooled cake. Top with muscatels; drizzle with syrup.
Muscat and tokay are both fortified wines available from liquor stores. You can also use sweet sherry or port. The brownie can be made a day ahead; store in anairtight container at room temperature.Note