6 tablespoons unsalted butter, at room temperature
¼ cup unsweetened cocoa powder
¼ teaspoon salt
1¼ cups powdered sugar
1 tablespoon milk
½ teaspoon vanilla extract
¼ cup heavy cream
3 tablespoons Ovaltine chocolate malt powder
Using an electric mixer, cream together the butter, cocoa powder, and salt on medium speed for about 3 minutes (mixture will be thick).
Scrape down the sides of the bowl and add the powdered sugar. Mix on low speed to incorporate the sugar, and while the mixer is running, slowly add the milk and vanilla extract. Gradually increase the mixer speed to medium-high, beating until smooth, scraping the sides of the bowl as necessary.
In a 1-cup measuring cup, or in a small bowl, mix together the cream and the Ovaltine. Reduce the mixer speed to medium, and pour the cream mixture in a slow, steady stream and mix until thoroughly combined. You can add more powdered sugar a tablespoon at a time, if you would like a stiffer frosting, or more cream if you would like it thinner.