Super Hot Fudge Sauce

4 oz Semisweet chocolate; coarsely chopped
5 tb Butter; unsalted
1/4 c Cocoa
3/4 c Sugar
3/4 c Water
1/4 c Corn syrup
2 ts Vanilla In heavy medium saucepan, combine the chocolate, butter, cocoa, sugar, water and corn syrup. Whisk over medium high heat until the chocolate and butter are melted and the sugar is dissolved. When the sauce just comes to a boil, reduce the heat to low and cook at a low boil for 8 to 10 minutes; the sauce will thicken as it cools.
Add the vanilla and stir to combine. Store in the fridge tightly covered.