This is a Cook's Country recipe that is kind of weird, but really good on a dark chocolate cake like Beatty's:
INGREDIENTS
20 tablespoons (2 1/2 sticks) unsalted butter, softened (60 to 65 degrees)
1 cup confectioners' sugar (4 ounces)
3/4 cup Dutch-processed cocoa
pinch table salt
3/4 cup light corn syrup
1 teaspoon vanilla extract
8 ounces milk chocolate, melted and cooled slightly (see note)
INSTRUCTIONS
In food processor, process butter, sugar, cocoa, and salt until smooth, about 30 seconds, scraping sides of bowl as needed. Add corn syrup and vanilla and process until just combined, 5 to 10 seconds. Scrape sides of bowl, then add chocolate and pulse until smooth and creamy, 10 to 15 seconds. Frosting can be used immediately or held (see note).