Sounds like one of the summer party scenes from The Great Gatsby, but it’s not. These oven-toasted mixed nuts are probably the easiest thing you can make for your own party, poolside or not. They come together in a minute and toast at a pretty low temp, so if you overshoot by a little bit they won’t burn.
There really is no recipe involved here, more like an overview. Take a heavy ovenproof pan (my choice, as usual, is a cast-iron skillet) and pour a tiny amount (1/2 teaspoon?) of oil into it. Add enough mixed nuts to cover the bottom of the pan in a single but full layer. My 12-inch cast-iron skillet holds about 2 cups mixed nuts. Sprinkle liberally with sea salt (Maldon is perfect for this) and toss to coat the nuts with oil. They should be barely glistening—too much oil makes them difficult to eat in a party setting. Add a few springs of rosemary (or thyme, or summer savory, or a mix) and put the pan in a preheated 250° F oven.
Stir them once or twice until they are nicely toasted, about 45 minutes. I leave them in the oven for up to 30 minutes. After that, turn the oven off and leave them in for longer. The rosemary will get very brittle and the leaves will fall off the stem. That’s a little added flavor bonus.
I like to serve these spooned into the kind of cone-shaped paper cups that used to be on the side of every water cooler. They’re not that easy to find, except online and at big-box stores. I like these nuts a lot but not enough to commit to 1,000 paper cups. So now I spoon them into little bowls and let people pass them around.
You can, of course, use whatever blend of nuts you like. Walnuts, pecans, cashews and Brazil nuts are good choices. Pistachios and hazelnuts, not so much. There’s nothing for the salt/oil/rosemary to grab onto.