Heat the oven to 250F and arrange a rack in the middle.
Remove the corn kernels from the cobs: Place a large container on a damp towel. Fold a paper towel into fourths and place it inside the container. Stand one ear of corn on the paper towel, using the stem as a handle. Using a paring knife, slice downward, letting the kernels fall into the container. Rotate the cob to get another row. Using the back of a knife scrape along the cobs to extract the milky liquid and add it to the bowl with the kernels. Discard the cobs. You need 2 cups of kernels (alternatively collect 2 cups drained canned corn).
Whisk flour, cornmeal, baking powder, salt, and cayenne pepper together in a bowl until combined. Whisk the milk and egg together in a small bowl until combined, add them to the flour mixture and stir until combined. Stir in the corn and scallions until evenly mixed; set aside.
Pour the oil into a Dutch oven or a large heavy-bottomed pot and heat over medium-high heta until the oil temperature registers 360F on a deep fry thermometer. Meanwhile, fit a wire rack over a baking sheet, set aside.
When the oil is ready, carefully drop 5 heaping tablespoons of the corn batter into it. Fry, turning ocassionally until dark golden all over, about 4 minutes. Be careful as some of the corn kernels may pop causing hot oil to spatter. Using a slotted spoon or spider skimmer transfer the fritters to the wire rack on the baking sheet and place in the oven to keep warm. Use the slotted spoon or spider to skim and discard any bits of fritter remaining in the pot. Repeat with the remaining batter.
Serve immediately - you can dip in tartar sauce if you like.