Hot Fudge Sauce

This is hot fudge as it's meant to be. Deeply chocolaty, it acquires an almost chewy quality when poured over ice cream. It's adapted from a recipe in Sweet Cream and Sugar Cones (Ten Speed Press, 2012; $25), by Anne Walker, Kris Hoogerhyde, and Dabney Gough.
How to Make It
Step 1
1
Mix cream, sugar, cocoa, corn syrup, and salt in a medium saucepan. Bring to a boil over medium-high heat and cook just until sugar has completely dissolved, about 3 minutes. Remove from heat.
Step 2
2
Add chocolates and vanilla and stir until chocolate is melted and sauce is completely smooth. If you have any lumps, gently press and smear them against the bottom of the pan with a spatula as you stir.
Ingredients
1 cup heavy cream
1 cup sugar
1/4 cup Dutch-process unsweetened cocoa powder, sifted
1/2 cup light corn syrup
1/2 teaspoon kosher salt
4 ounces bittersweet chocolate (about 60% cacao), finely chopped
4 ounces unsweetened chocolate, finely chopped
1 teaspoon vanilla extract