In a medium saucepan, blend 2 cups sugar, 5 tablespoons flour, 1 teaspoon salt, ⅔ cup cocoa powder and 1 tablespoon instant espresso powder (if using).
Add 12 ounces evaporated milk, ½ cup water and 2 tablespoons butter.
Cook over medium heat, stirring constantly until sauce bubbles and thickens, about 5-8 minutes.
Remove from heat and stir in ½ teaspoon vanilla extract.
Serve over ice cream.
Video
Notes
Hot fudge doesn't sit nicely on top of ice cream -- it slicks and slides down the side, creating a fudge dam at the base of your dessert. It's wonderful.