I made this recipe over and over last year to pack in Christmas tins for my kids and others. Nana used to make this toffee recipe every Christmas, and I so love toffee. I have Nana's recipe here. I remember long ago when we still lived in the house on Allen Circle her getting out her toffee making pan (the one with teflon coating) and stirring up a batch of toffee at Christmas. Now we have scilipats to make our lives easier. I've never had a hard time getting the toffee out of the pan when I use one. Nana gave me my first scilipat and she loved how easy they made candy and baking. After many years, she went to her famous fudge recipes. For my fellow toffee addict Taylor, and all of you, here is the recipe for Nana's wonderful toffee…Butter a 12 x 18 (half sheet cake) baking sheet, cover with chopped pecans (or walnuts)
and set aside. You can also use a scilipat baking sheet (minus the butter) in your baking sheet for great results. They are the perfect size to fit a half sheet cake pan. (pictured above with the ingredients).
In a heavy bottomed 3 qt. saucepan…
2 C. Butter (1#) not margarine
1/2 C. Water
1/4 C. Light corn syrup (Karo)
2-1/2 C. Sugar
Combine above ingredients over medium high heat and stir with a wooden spoon until mixture comes to a boil. Continue stirring until mixture begins to thicken. Reduce heat to low, remove wooden spoon and do not continue to stir.
Clip on candy thermometer and cook syrup to 290ºF (or 145ºC), a soft crack stage.

Remove from heat and pour over pecans in prepared baking sheet.

When just hardened, but still hot:
Sprinkle 1 pound (or so) chocolate chips on candy. Sprinkle densely. After just a few moments chips are soft so you can spread evenly to coat candy.

While chocolate is still warm, sprinkle finely chopped walnuts (2-4 cups) over top and gently press to set nuts into chocolate. After cooled completely you can turn entire block over, melt some more chocolate chips to spread over the back side and coat with nuts. Double coated is good, but a lot more work. I usually just do the one layer chocolate.
Any kind of nuts you like will work, and milk chocolate or semi-sweet chocolate chips - whatever your tastes are.
When completely cooled:
I use a clean white dishtowel to turn the toffee out on. I loosen the edges with a sharp knife and then lay the baking sheet upside down over the dishtowel. After the toffee is out of the sheet, peel off the scilipat and turn the whole block over so the chocolate and nuts are once again on top. Break into irregular pieces and store in an airtight container.
Makes 4-5 pounds (about 150 pieces).
Sometimes syrup mixture separates during cooking leaving a buttery looking layer on the surface and a thicker mixture underneath. To save the batch try and correct, add about 1/2 C. hot water and stir well. You may need to add additional hot water, but this should correct and save your batch. I've never had to do this, but got this tip from a candy book.
Taya sent me a pic of the toffee tin they got at Christmas. Thanks Taya.