PRE-HEAT the oven to 250° F (121° C).

LINE 4 half sheet pans with parchment.

SET UP a large heavy pot (6 or 7 quart capacity). I use a Le Creuset 7 1/4 quart Dutch oven for both popping the corn and cooking the caramel. Having a large enough pot is very important because you don't want the caramel to boil over. To check the size of your pot, set it in the sink and fill with quarts of water until it is full. Also, have a thermometer handy; I like to use a digital probe thermometer. Note: If you have an electric popcorn popper, you can use that to pop the corn.

POP THE CORN: For each batch, pour oil into pot and add several kernels of popcorn. When the kernels pop, add the rest of the popcorn and pop over medium-high heat with the lid partially ajar, (or use a pizza screen), shaking occasionally. Lift the popped corn out of the pot, leaving the unpopped kernels behind. Very important not to have unpopped kernels in the finished Caramel Popcorn; they can ruin the results and break a tooth. Place each batch of popcorn in a separate large stainless steel bowl. One of the bowls should be large enough to hold the whole batch. If you have an electric popcorn popper, you can use that for popping the corn. Clean the pot and use for making the Caramel Syrup.

COOK THE CARAMEL SYRUP: MELT the butter in same pot used for popping the corn. Add the brown sugar, corn syrup, hot water, and salt. Stir over medium heat until the sugar dissolves completely; stop stirring when the syrup comes to a boil. Brush down sides of pan with water as needed to keep the sides clean.

CLIP a candy thermometer to the inside of the pan or use a probe thermometer. COOK, without stirring, until the mixture reaches 260° F (127° C) (hard ball stage). Remove the pan from the heat and quickly stir in the baking soda and vanilla. Stir in cold water to stop cooking. Add cashews.

DRIZZLE half the hot caramel, using a large ladle, over one bowl (the large one) of popped corn. Toss gently with 2 wooden spoons, or a wooden spoon and a red-handle heat-resistant rubber spatula, until all the popcorn is well coated. Add second bowl of popcorn and drizzle with balance of caramel. Make sure caramel is evenly distributed and all popped kernels evenly coated.

DIVIDE among the four half sheet pans. Spread evenly in pans.

BAKE IN TWO BATCHES - Two pans at a time: For each batch, BAKE 30 minutes at 250° F (121° C). Stir the popcorn gently and rotate the pans. Turn down the oven to 225° F (107° C) and BAKE another 30 minutes. Total baking time = 1 hour.

REMOVE the pans from the oven. Separate the kernels of popcorn while still hot. Caution! The popcorn will be extremely hot. Use vinyl gloves if necessary. Allow the caramel corn to cool completely.

TRANSFER the baked popcorn from the pans to a large bowl and toss with the dried cranberries until evenly distributed.

STORE the caramel popcorn in an air-tight container at room temperature for up to a month. Or, pack into plastic bag Ziploc bags.