Step 1

In a medium saucepan, bring the can of evaporated milk and 2 cups sugar to a rolling boil over medium low heat, stirring with a wooden spoon. Babysit the pot a little bit and stir frequently, especially as is starts to come to a boil. It will take several minutes to come to a boil.

Step 2

Stir constantly once it is at a rolling boil (keep the heat at medium low) and let boil for 1 minute.

Step 3

Add in 4 ounces unsweetened chocolate squares. Exchange your wooden spoon for a whisk and beat the chocolate vigorously, turning the heat to low. Beat until the chocolate has smoothed out and no longer looks grainy. The better of a job you do here whisking, the smoother and creamier your chocolate sauce will be.

Step 4

Turn off the heat. Add 1/4 cup butter to the mixture. Beat until melted.

Step 5

Add 1 teaspoon vanilla extract and 1/2 teaspoon kosher salt.

Step 6

Let the hot fudge sauce sit at room temperature for 15-20 minutes to cool and thicken up.

Step 7

You can spoon it over ice cream immediately (or into your mouth--don't burn your tongue!) or pour it into jars or a tupperware to save for later. The recipe makes about 3 cups, so a quart jar will hold it all.

Step 8

The mixture will become much thicker in the fridge, but won't solidify completely. To reheat, just stick it in the microwave. The nice thing about this sauce is that you can microwave and refrigerate it several times and it won't separate or go grainy on you. It's the best!