There are many variations of butter crunch today. I favor the recipe I grew up with. It's tender and has just the right ratio of candy to chocolate to nuts. If you are going to make this, I highly recommend you purchase a good candy thermometer. Interestingly, I have had trouble making it everywhere I have lived since leaving NY. Relative humidity is likely the biggest culprit, but for some reason, this year, it turned out perfectly! This recipe dates back to at least the 1960's.
Butter a sheet pan lightly and set it on a trivet or hot pad of some sort. Add ice water to a measuring cup for testing and have it near by.
Caution, candy making is dangerous as it is VERY HOT. Warn your family not to touch the sheet pan once you've poured the candy. Let cool entirely. Heat 12 oz Semi Sweet Chocolate (such as Nestle's Semi Sweet Chips) in a saucepan over very low heat just until melted. Spread 1/2 of it onto the toffee. Top with 1/2 Cup Ground Walnuts and push slightly into the chocolate. Once cool, turn over the toffee using an off set spatula and repeat using the remaining chocolate and another 1/2 Cup Ground Walnuts. Once cooled completely, break the toffee by hand. Store in an airtight container. Thanks Mom!