Smoke the corn according to the directions below. When it is cool enough to handle, strip the kernels from the cobs.
Pour enough cold water over the potatoes in a 3-quart saucepan to cover them by a few inches. Bring the water to a boil over medium-high heat, then adjust the heat so the water is at a gentle boil. Cook until the potatoes are tender when poked with a fork, 20 to 30 minutes, depending on the size of the potatoes. Drain the potatoes, and cool them to room temperature. Peel them, if you like, and cut them into 1/2-inch slices.
Position the rack in the center of the oven and preheat the oven to 325 degrees F.
Heat 3 tablespoons of the olive oil in a 10-inch cast-iron skillet over medium heat. Stir in the onions, season them lightly with salt and pepper and cook, stirring occasionally, until they are wilted but not browned, about 6 minutes.
Beat the eggs, milk and 1 1/2 teaspoons salt together in a large bowl until thoroughly blended. Stir in the corn kernels and cheese.
Add the remaining 2 tablespoons olive oil to the pan and swirl it around to coat the sides as much as possible. Gently stir the sliced potatoes into the skillet and cook them a minute or two to warm them through.
Reduce the heat to medium-low and pour the egg mixture into the skillet. Don't stir. In about a minute, the egg should begin to bubble in a few spots around and near the edges. If it starts to bubble sooner, lift the pan from the heat and reduce the heat slightly. Wait a minute and return the pan to the heat. Cook until the edges are lightly browned (check by carefully slipping a thin metal spatula or knife along the edge of the tortilla), about 5 minutes.
Set the skillet in the oven and cook until the top is puffed and brown and the center is firm to the touch, 25 to 30 minutes.
Serve the tortilla hot after letting it rest 5 minutes, warm after resting 30 to 40 minutes, or cooled completely to room temperature. In any case, run a thin, flexible spatula around the sides, then underneath to make sure the tortilla hasn't stuck to the pan. Serve the hot tortilla right from the pan.
You can serve the warm or room temperature tortilla from the pan as well or, if you're feeling adventurous and have strong wrists, invert it onto a plate as follows: make sure the tortilla is not stuck to any part of the pan. Cover the pan with a plate that is at least 2 inches wider than the pan. Working about one foot over a counter, hold the handle of the skillet with one hand and clamp the plate over the top of the skillet with the other. Invert the skillet over the plate in one quick motion, then lower the plate onto the counter and lift off the skillet. You can also cut the tortilla into wedges in the pan and lift them to individual serving plates.
Smoked Corn on the Cobb:
1 1/2 to 2 1/2 tablespoons of alder, cherry or corn cob chips
4 ears corn
Olive oil or vegetable oil, for seasoning
Trim the husk and as much of the silk as you can from the ears.
Season the corn by rubbing the ears lightly with olive or vegetable oil.
Smoke the kernels until they are tender and browned, about 20 minutes, checking the corn for doneness after about 15 minutes.
Yield: 4 ears of corn will yield about 1 1/3 cups smoked kernels