Making Classic English Toffee is straightforward if you follow these step-by-step instructions:

1. Prepare the Baking Sheet: Line a 9×13 inch baking dish with parchment paper, allowing some overhang for easy removal later.
2. Melt the Butter: In a medium saucepan over medium heat, melt the unsalted butter completely.
3. Combine Ingredients: Add the granulated sugar, light corn syrup, and salt to the melted butter. Stir until well combined.
4. Cook the Mixture: Bring the mixture to a boil, stirring constantly to prevent burning. Cook until it reaches a deep amber color (about 300°F or 149°C on a candy thermometer).
5. Add Vanilla: Once the desired color is achieved, remove the saucepan from heat and quickly stir in the vanilla extract.
6. Pour into Baking Dish: Immediately pour the hot toffee mixture into the prepared baking dish, spreading it evenly with a spatula.
7. Cool Slightly: Allow the toffee to cool for about 5 minutes.
8. Add Chocolate: Sprinkle the semi-sweet chocolate chips evenly over the warm toffee. Let them sit for a couple of minutes to soften.
9. Spread the Chocolate: Use a spatula to spread the melted chocolate over the toffee evenly.
10. Add Nuts: If desired, sprinkle the chopped nuts over the chocolate layer, pressing them down gently.
11. Cool Completely: Let the toffee cool at room temperature for about 30 minutes or until completely set. You can also refrigerate it for faster cooling.
12. Break into Pieces: Once set, use the parchment overhang to lift the toffee out of the dish. Break it into pieces of your desired size.

By following these steps, you’ll create a batch of Classic English Toffee that is sure to impress!