Okay, I just gotta hip ya'll to this stuff. I've been making it for holiday treats for 3 years, and every time I'm struck anew by how insanely great it is. And how spectacularly addictive.
The recipe originally came from Francois Payard's "Simply Sensational Desserts", but I've revised it some (after totally f***ing it up a few times). This is not recommended as your first foray into candymaking, as it's rather persnickety.
1 1/4 c. (290 g) heavy cream
2 tbsp (41 g) light corn syrup
1 2/3 c. (334 g) sugar
2 3/4 c. (400 g) macadamia nuts, crushed
METHOD (Don't try this without a candy thermometer)
Line a cookie sheet or 1/2 sheet pan with parchment paper. Better yet, if you have a marble slab, oil it lightly with neutral vegetable oil (peanut or canola) and have it standing by. Also have a rolling pin and a sheet of parchment on call.
Combine the first 3 ingredients in a heavy saucepan large enough to hold 4 times the volume of these ingredients (this should save you having the whole mess boil over). Bring to a boil over slightly hotter than medium heat while stirring to dissolve the sugar. Continue boiling, without stirring, until the mixture starts to turn a pale golden color, and from this point on give it your UNDIVIDED attention. Stick the candy thermometer in the pan and DO NOT be tempted to up the heat (the temperature will rise painfully slowly). Using a wooden utensil with a flat edge, stir occasionally at first and then constantly as the temperature approaches 260°F. Keep boiling and stirring until the mixture reaches 284°F.
Turn off the heat and dump the nuts into the pan, stirring vigorously (the mixture will stiffen very quickly). When the nuts and toffee are well combined (gotta work FAST), dump the whole mass out onto the prepared cookie sheet or marble slab. Place the sheet of parchment over the toffee and roll it out with the rolling pin, using lots of muscle, until it's about 3/8 inch thick. Let cool completely, then break into irregular shapes and store in an airtight container.
Crushing the macadamia nuts is easier if you freeze them first. Then put them in a large Ziploc bag and hammer them with a mallet or some such. Try not to hit them more than twice, or you'll end up with something resembling macadamia paste instead of the desired chunks. Let the nuts come back to room temperature before proceeding with the recipe.