To make the mayo, whisk the Egg (1), Dijon Mustard (1 tablespoon), and Apple Cider Vinegar (1 tablespoon) together really well, then keep whisking while you slowly pour in the Canola Oil (1 cup). Keep whisking until you have a thick, gorgeous mayo.
Then add 1/4 cup of either the homemade mayo or jarred Mayo and stir it in to bring Shredded Extra Sharp Cheddar Cheese (8 ounce), Pimiento Pepper (1 jar), and Scallion (1 cup) together.
Set aside any homemade mayo left, there will be about 3/4 cup left, sealed in the fridge for further use. Seal up the pimento cheese too and use it in countless ways! It's a fantastic dip on its own, grilled cheese filling or burger topping. Enjoy!