Step 1

Add butter, sugar, salt, and water to a heavy pot. Turn stove to medium and bring to a boil.

Step 2

Stir periodically if you choose, and add candy thermometer once the mixture boils.

Step 3

While candy cooks, place a silpat on a jelly roll pan to contain the toffee and chop chocolate.

Step 4

Cook candy to 300 degrees, then pour the toffee onto the silpat. Smooth the toffee with a spatula and spread it to desired thickness.

Step 5

Give it a minute, then use a pizza wheel to score the toffee. Immediately top with chopped chocolate.

Step 6

Let residual heat from the toffee melt the chocolate. Use a new spatula to smooth the chocolate over toffee.

Step 7

Let the chocolate harden for an hour. To finish, lift one edge and gently break it along the score lines.

Step 8

Serve immediately, or place in a tightly sealed container and store on your counter for up to a month.