Chocolate Fudge Frosting

Before you start

A good chocolate fudge frosting tastes like chocolate first and sugar second. This one uses two sources of chocolate: Dutch-process cocoa for deep, dark flavor and color, and melted bittersweet chocolate for a dense, fudgy body that sets with a soft sheen. Butter carries the flavor, a little powdered sugar sweetens and thickens, and cream loosens it to a smooth, swoopy texture that spreads easily over a sheet cake without tearing the crumb.

The melted chocolate must cool before it goes in. Hot chocolate melts the butter and leaves a greasy, sliding frosting; chocolate that is too cold firms into tiny specks. Aim for about 30°C (86°F), when it still pours but feels barely warm on your lip. A pinch of instant espresso and a good amount of salt sharpen the chocolate flavor without making it taste of coffee.

Ingredients

• 115 g (4 oz) bittersweet chocolate, 60–70% cacao — chopped
• 225 g (1 cup) unsalted butter — softened
• 300 g (2½ cups) powdered sugar — sifted
• 60 g (¾ cup) Dutch-process cocoa powder — sifted
• ¼ tsp fine salt
• 1 tsp instant espresso powder — optional
• 80 ml (⅓ cup) heavy cream — room temperature
• 2 tsp vanilla extract

Method

1. Melt the chocolate in a heatproof bowl over barely simmering water, or in the microwave in 20-second bursts, stirring until smooth. Let it cool, stirring occasionally, until it reaches about 30°C (86°F).
2. Dissolve the espresso powder, if using, in the cream. Sift the powdered sugar and cocoa together into a bowl; cocoa clumps easily and lumps will not beat out.
3. Beat the butter on medium-high speed for 2 to 3 minutes, until creamy and lighter in color.
4. On low speed, add the sugar and cocoa mixture in three additions, alternating with the cream, starting and ending with the dry mixture. The frosting will be thick and dark.
5. Add the cooled melted chocolate, salt and vanilla. Beat on medium-high for 2 minutes, until fluffy, smooth and a shade lighter.
6. Spread the frosting on a completely cooled cake right away. Use the back of a spoon or an offset spatula to make swoops and swirls; it sets with a soft, satiny surface over an hour or so.

Tips for success

• If the frosting gets too stiff while you work, beat in 1 tbsp of warm cream. If it is too loose, chill the bowl for 10 minutes.
• For a darker, almost black frosting, use part black cocoa in place of some of the Dutch-process cocoa. It tastes more like a chocolate sandwich cookie.
• Use the frosting at room temperature; chilled, it becomes firm and dull and needs re-beating.

Substitutions

Dutch-process cocoa

Natural cocoa works since there is no leavening involved. The color is redder and the flavor sharper and fruitier.

Bittersweet chocolate

Semisweet chocolate chips work but make a sweeter frosting. Melt them gently, as chips contain stabilizers and scorch easily.

Heavy cream

Whole milk gives a slightly lighter, less rich frosting. Strong brewed coffee in place of the cream boosts the chocolate flavor.

Variations

Mocha fudge frosting

Increase the espresso powder to 1 tbsp and use cooled strong coffee instead of cream.

Peanut butter fudge frosting

Replace 55 g (¼ cup) of the butter with creamy peanut butter.

Troubleshooting

Frosting is greasy or runny

The chocolate was still hot or the butter was too soft. Chill the bowl for 15 minutes, then beat again until fluffy.

Tiny hard chocolate specks

The melted chocolate was too cool and seized into bits when it hit cooler butter. Warm the bowl briefly over warm water while beating to melt the specks.

Bitter or chalky taste

Too much cocoa for your taste or not enough salt and sugar. Beat in another pinch of salt and 30 g powdered sugar.

Storage

Keep the frosted cake covered at cool room temperature for up to 2 days. Store leftover frosting in the refrigerator for up to 1 week or freeze for up to 3 months; bring to room temperature and re-beat before using.