24 ounces semisweet chocolate chips
1 quart heavy cream
1 tsp. light corn syrup
Place chocolate and cream in a heavy saucepan. Cook over medium-low heat, stirring constantly with a rubber spatula, until combined and thickened, 25 to 35 minutes. Increase heat to medium cook, stirring, about 10 minutes more.
Remove from heat; stir in corn syrup. Transfer to a metal bowl; chill. Stir every 15 to 20 minutes; stir until cool enough to spread, 2 to 3 hours. You can also do an ice bath to cool it down if desired.
Put on top of a yellow cake.