Vegetable-oil spray or 1 teaspoon butter, for lining the tray
2 cups sugar
4 ounces (1 stick) salted or unsalted butter
1/3 cup light corn syrup
1/2 teaspoon baking soda
2 teaspoons to 1 1/2 tablespoons coarse or flaky sea salt (use less if you’re using salted butter)
1 1/2 cups of raw, unroasted pepitas (they toast in the syrup) or 12 ounces (3/4 pound) roasted, salted nuts, not chopped