Pimento cheese: grate cheddar in a food processor or on a hand grater.
Add cheese to a large bowl with sugar, Miracle Whip, or mayonnaise and stir to combine.
Add everything back to the food processor with the blade attachment instead of the grating attachment.
Pulse the processor until you get your desired consistency.
Add half of the pimentos and some of the liquid from the jar. This will loosen the cheese mixture in the food processor a little and should allow it to become a bit smoother.
When the cheese mixture looks like it would be spreadable, taste it and add any salt and pepper that it might need.
Add the remaining pimentos and all the liquid from the jar and pulse one or two more times. This will allow your pimento cheese to have visible pimentos in it. If you add the pimento all at the beginning, you will blitz it until it's all too small to see.
Package up the pimento cheese in a sealed container and store it in the fridge for a week or so.
Red pepper relish: drain the hot cherry peppers and reserve the liquid.
Add the drained cherry peppers and 1 teaspoon of the liquid to a food processor along with the red bell pepper pieces, onion, and garlic. Pulse everything in the food processor until it looks like a thick salsa.
Place a medium-sized skillet over medium heat and add 1 teaspoon of olive oil.
Move everything from the food processor to the skillet and saute, stirring for 4 or 5 minutes. Add the sugar, white vinegar, salt, and MSG (if using) and continue to cook, stirring often for 20 minutes to reduce some of the liquid.
Remove the pan from the heat and allow everything to cool for about 5 minutes. After the relish has cooled a little you can move it straight to a jar or you can strain it to remove some of the extra liquid. Any excess liquid works great when mixed into a salad dressing.
Store the relish in a jar or sealed container in the fridge for up to 4 weeks.
Sandwich assembly: slice a sandwich roll lengthwise and apply some mayonnaise to the bottom piece of bread.
Top the mayonnaise layer with a pile of sliced turkey and then spread pimento cheese on the other side of the roll.
Top the turkey with a handful of shredded lettuce and then spoon some red pepper relish on top of the lettuce. Close the sandwich and serve.