Remove husks and strings from corn cob, then rub it all over with softened butter. Season with salt and pepper. Place on parchment or foil-lined sheet pan and roast 30 minutes, rotating it every 10 mins as it cooks.
Remove the corn from the oven, let cool slightly, and use a sharp knife to remove the kernels from the cob.
Combine corn kernels with jalapeño, cheese, garlic, scallions, and cilantro in a bowl. Then add the egg and salt and stir to evenly incorporate. Add the flour last, starting with 3 tablespoon and adding an additional 1 tablespoon if it doesn't seem like it's holding together. The finished corn fritter "batter" should be fairly loose but should mostly stick together when you scoop it.
Heat a generous glug of olive oil in a skillet over medium heat. Test if the skillet is hot enough by dropping one kernel of corn into the skillet — if it doesn't immediately start bubbling, the skillet isn't hot enough.
Use a ¼ or ⅓ cup scoop to transfer dollops of the batter into the skillet. Use a spatula or the bottom of the measuring cup to press down on the top of the fritter and flatten them to about ¼" tall. Cook approx 3-4 mins per side. Remove to a paper towel to drain.
While the fritters cook, mash an avocado with lime juice, salt, pepper, thinly sliced scallion, and cilantro in a small bowl. Dollop on top of corn fritters to serve.
RECIPE NOTES
Whether you want several small corn fritters or one or two giant corn fritters, the cook time is mostly the same. If you're making a really big corn fritter, add an extra 30-60 seconds per side, but keep an eye on it — corn cooks quickly and you don't want it to burn!