Both of my favorite chocolate frostings are from Cook’s Illustrated. Or course, use the best chocolate you can find, not chocolate chips. The first recipe is a bit involved, but not difficult to make. Both are smooth, creamy, fluffy, and billowy; neither is overly sweet, neither is like ganache.
Chocolate Fudge Frosting Cooks Illustrated March/April 2006
16 ounces semisweet chocolate, finely chopped
8 tablespoons unsalted butter
1/3 cup sugar
2 tablespoons corn syrup
2 teaspoons vanilla
1/4 teaspoon table salt
1 1/4 cups cold heavy cream
Melt chocolate and set aside. Melt butter. Increase heat to medium and add sugar, corn syrup, vanilla and salt. Stir with a heatproof rubber spatula until sugar is dissolved, 4-5 minutes. Add melted chocolate, butter mixture and cream to the bowl of a standing mixer and stir to thoroughly combine. Place mixer bowl over ice bath and stir mixture constantly with a rubber spatula until frosting is thick and just beginning to harden against sides of bowl, 1-2 minutes. Frosting should be 70 degrees. Place bowl on standing mixer fitted with paddle attachment and beat on medium-high speed until frosting is light and fluffy, 1-2 minutes. Stir with rubber spatula until completely smooth.
Foolproof Chocolate Frosting Cooks Illustrated March/April 2008
This frosting may be made with milk, semisweet or bittersweet chocolate. Cool the chocolate to between 85 and 100 degrees before adding it to the butter mixture. The frosting can be made 3 hours in advance. For longer storage, refrigerate the frosting, covered, and let it stand at room temperature for 1 hour before using.
20 tablespoons unsalted buttered, softened to 60-65 degrees
1 cup (4 ounces) confectioners’ sugar
3/4 cup Dutched cocoa
Pinch table salt
3/4 cup light corn syrup
1 teaspoon vanilla
8 ounces chocolate, melted and cooled slightly
In food processor, process butter, sugar, cocoa and salt until smooth, about 30 seconds, scraping sides of the bowl as needed. Add corn syrup and vanilla and process until just combined, 5-10 seconds. Scrape sides of bowl, then add chocolate and pulse until smooth and creamy, 10-15 seconds. Frosting can be used immediately or held (see above).