Ingredients

4 ounces butter
1/2 cup port wine
5 ounces unsweetened chocolate
1 cup granulated sugar
3 eggs, separated
3/4 cup all-purpose flour
1/8 teaspoon salt

Method

1. Preheat oven to 350 degrees. Butter and flour one 9 or 10-inch cake pan.
2. Melt butter and chocolate together in small saucepan. Add wine in quarters, stirring slowly until last addition is thoroughly incorporated before adding the next quarter. (If you go too fast it will break!)
3. Combine sugar and egg yolks in bowl and mix on medium speed until pale yellow in color. Add melted chocolate slowly and beat until smooth. Add flour and beat on medium speed for 1 minute.
4. In another bowl, beat egg whites on high until stiff peaks form. Gently fold in 1/3 of chocolate mixture into egg whites. Fold in remaining chocolate carefully.
5. Pour into cake pan and bake for 30 minutes.