In America, people often think of toffee as a chewy, sticky candy. Of course, toffee's first appearance in the Harry Potter series is during a very hot and sticky "road trip," so maybe that contributes to the misconception:
"This, thought Harry, was surely the way to travel-- past swirls and turrets of snowy cloud, in a car full of hot, bright sunlight, with a fat pack of toffees in the glove compartment, and the prospect of seeing Fred's and George's jealous face when they landed smoothly and spectacularly in the sweeping lawn in front of Hogwarts castle" (Chamber of Secrets 71).
English toffee is much more like the hard toffee you might find in the middle of a Heath Bar. There are several recipes out there, including one in The Unofficial Harry Potter Cookbook. Though slightly modified, that is basically the recipe I will use.
You Will Need (this includes my modifications):
1 cup granulated sugar
1/2 cup golden syrup or light corn syrup
1.5 sticks salted butter
1/2 cup heavy cream
1/4 tsp cream of tartar
1 tsp vanilla
your favorite chocolate, chopped (I used milk chocolate chips)
1. Grease a rimmed baking sheet and line it with parchment or wax paper, allowing the paper to climb up the sides on at least 2 sides.
2. Place the sugar, golden syrup, butter, heavy cream, and cream of tartar in a medium-large saucepan and cook over medium-high heat, stirring constantly, until completely combined.
3. Reduce the heat to medium-low (wash the sides down with a pastry brush dipped in water if any sugar crystals form).
4. Using a candy thermometer, continue to cook, stirring constantly (this really is important!), until the temperature reaches 260 degrees (Dinah Bucholz' recipe calls for it to be way hotter).
5. Remove the pan from the heat and quickly (but carefully!) stir in the vanilla.
6. Immediately pour the mixture onto the prepared baking sheet. Move quickly, because it will start to harden pretty fast. Allow it to cool completely, without putting it in the fridge.
7. Melt the chocolate in the microwave and pour/spread it over the hardened toffee.
8. Place the chocolate-covered toffee in the fridge for 10 minutes or until the chocolate sets.
9. Peel the toffee off the wax paper and break it into irregular pieces.
This is some tasty candy, my friends! And I really think cooking it to the lower temperature (260 degrees versus the 300 called for in the cookbook), yields a much better toffee that is hard, but gets pleasantly chewy after a few moments in your mouth. If you like, you could certainly press some chopped nuts into the chocolate before it sets, creating a more classically English Toffee. But however you decide to prepare it, be sure to enjoy! And maybe imagine you're in a flying Ford Anglia on your way to your next year at Hogwarts!