Line a baking sheet with parchment paper and lightly grease the parchment paper with butter.
Sprinkle chopped almonds and cashews onto the parchment paper lined pan and spread out evenly. Set aside.
In a medium sized saucepan combine the sugar, butter, water and corn syrup. Over medium heat stir constantly until the butter is melted and the sugar is dissolved.
Once the mixture starts to bubble, stop stirring and place a candy thermometer into the pot.
Cook until the mixture reaches 260°F.
Remove from heat and stir in vanilla extract. The toffee mixture will bubble vigorously when the vanilla is added.
Pour the toffee mixture overtop of the almonds and cashews on the baking sheet. Taking care to pour the mixture evenly over the entire baking sheet.
Immediately sprinkle the chocolate chips all over the top of the toffee on the baking sheet. Let rest for 5 minutes until the chocolate chips begin to melt.
Using an offset spatula spread the chocolate evenly over top of the toffee.
Transfer the toffee to the refrigerator and let set for a minimum of 2 hours, until the toffee is fully set.
Once the buttercrunch toffee is fully set, remove it from the fridge and using a knife, carefully break the toffee into chunks.
Notes
- Store buttercrunch toffee in an airtight container at room temperature for up to 2 weeks.