1 cup heavy whipping cream
3/4 cup butter, cubed
1 1/3 cups packed brown sugar
1/4 cup granulated sugar
pinch salt
1 cup unsweetened cocoa powder
1/2 cup plus 2 tbsp light corn syrup
2 squares (1-oz each) unsweetened chocolate
3 tsp vanilla extract
1-2 tsp rum extract
In a heavy saucepan, combine cream and butter. Cook and stir over medium-low heat until butter is melted. Add the sugars and salt, and cook until sugar is dissolved, stirring constantly; about 4 minutes. Stir in the cocoa and corn syrup; cook and stir for 3 minutes.
Add the chocolate and cook and stir for 3-4 minutes or until chocolate is melted. Reduce heat to low. Simmer for 12-16 minutes or until desired thickness is reached, stirring constantly. Remove from heat; stir in the extracts. Cool slightly. Serve warm over ice cream. Refrigerate leftovers.