I was looking to make a non-cookie treat and a trip through my grandmother's old recipe box yielded a card in my grandfather's handwriting for English Toffee. [As far as I can tell, it's an American creation, where "English" means slathered with chocolate.] My grandmother made a lot of sweets, but my grandfather always made the candy, using a scientific thermometer permanently borrowed from his chemistry lab to monitor the temperature of the sugar.
I grew up hearing stories about Grandpa and his chemistry candy thermometer, but I've since learned you don't actually need to take the sugar's temperature if you're making a simple caramel or toffee. It'll be at the hard crack stage once it starts taking color, so you can just pull it off the stove when it's a little lighter than you want the final candy to be and let it sit in the hot pot until it reaches that caramel brown color. It's easy, but it rarely fails to impress.
Another thing about toffee specifically is that the butter will separate out a bit, which then, in English toffee gets combined with the chocolate to make a rich top coating. I was able to reduce the butter from 16 tablespoons to 6 [browning 2 of them for more flavor] without a problem. I mean, it's still a candy made from sugar and butter, but reducing the fat never hurts.
I also have a trick to keep the chocolate from getting too soft in a warm room, but for that, you'll have to follow the recipe...
Recipe: Jack's Granddaughter's English Toffee
Grandpa's recipe calls for pecans, though it seems walnuts would be more "English".
6 Tbs butter [divided use]
1 cup sugar
1 Tbs amaretto
3 oz dark chocolate, chopped
1/2 cup pecans, toasted and chopped
Place a cookie sheet into the oven and set to 400F.* Oil an 8x8 metal pan close to the stove. In a heavy bottom pot, brown 2 tablespoons of butter over medium high heat. Once the butter solids turn the color of almond skins, add remaining butter, sugar, and salt, and stir until the butter melts and sugar liquifies. Boil, stirring occasionally, until mixture is a rich caramel color, just a shade lighter than desired. Stir in amaretto [mixture will sputter] and pour into the prepared pan. Wait 3 minutes for the toffee to set, then sprinkle with chocolate. Wait another ~2 minutes for the chocolate to mostly melt, then spread with an offset spatula or knife. Remove cookie sheet from the oven and place over the toffee pan. Let it sit for 3 minutes, [turn off the oven meanwhile] then remove. Sprinkle with toasted nuts and allow to cool until chocolate is firm to the touch, ~30-45 minutes. Turn toffee out of the pan and cut with a sharp knife or break into pieces. Store in an airtight container.
* The pan over the top will heat the chocolate further and help retemper it... without melting your toffee. [FYI: if you're making those cookies with the Hershey's Kiss in the middle, it's also best to pop those bad boys back in the oven for a couple minutes after adding the kisses; they'll actually re-solidify faster and harder.]