Averie Cooks

-1 Line a 9x13-inch pan with parchment paper; set aside.
-1 If you have a clip-on candy thermometer, attach it to a heavy, high-sided saucepan. (If your thermometer doesn't clip, that's okay.)
-1 Add the butter, sugars, salt, and cook over medium-low heat, stirring constantly, until the mixture boils. After it boils, don't stir.
-1 Boil mixture until the 'hard crack' stage, 290-300F, without stirring (stirring can cause the finished toffee to become grainy or crystallize). It will probably take 20-25-ish minutes to come up to temperature if you're cooking over a true medium-low. At 290-300F, remove the pan from the heat.
-1 Cautiously stir in the vanilla (it will bubble up).
-1 Pour mixture into the prepared pan and let it sit for about 5 minutes before evenly sprinkling the chocolate chips over the toffee. Tip - Add one chip and if it sinks into the toffee, wait another few minutes before adding the chips.
-1 Cover the pan with foil for about 5 minutes, remove the foil, and spread the chocolate chips smooth with a spatula or off-set knife. Tip - If you chips have not melted (some brands are more resistant to others to melting and/or your toffee may have taken awhile to set up), put the pan in a 300F oven for a few minutes, or just until chips can be spread smooth.
-1 Optionally sprinkle with nuts, sea salt, sprinkles, etc., to taste. For this batch, I used pecans with sea salt, sea salt, holiday sprinkles, and plain.
-1 Let the toffee cool completely before in the fridge for about 30+ minutes, or until set. Break toffee apart with your hands or cut it with a sharp knife.