Place the wings in a large mixing bowl. Add the salt and white pepper, toss to coat the wings evenly. Place the wings in rows on the cookie sheet, leaving a little space between each wing.
Place the cookie sheet in the preheated 450 degree oven, and bake for 20 minutes. Flip them over and cook for about 10 minutes more.
While they cook combine the root beer, brown sugar, smoked paprika, chipotle powder in a small saucepan. When you drop the sugar into the root beer it will fizz up, it's okay, totally normal. Bring to a boil over medium-high heat, whisking as you go along. Once it boils, add the cornstarch slurry. If you are not sure how to make a cornstarch slurry it's actually really easy and will prevent lumps. All you have to do is grab a small mason jar with a lid, then add just a little bit of the hot root beer sauce to the jar, about 1/2 cup. Then add the cornstarch to the jar, pop the lid on, secure the lid, then shake the jar. You now have a slurry.
Add the slurry back into the saucepan, and whisk to keep it moving so it becomes smooth and starts to thicken. Once it thickens you remove from the heat.
At this time take the wings out of the oven, transfer to a mixing bowl (keep your pan out, the wings are going back in the oven to caramelize) and pour about half the liquid into the bowl. Set the other half aside for dipping wings into, if you dig that kind of thing.
Now toss the chicken wings in the sauce to coat evenly. Pour them back onto the cookie sheet and spread them out evenly. Place the cookie sheet back in the oven and cook for about 8 to 12 minutes, depending on how crispy you like your wings. I like to cook mine for about 5 or 6 minutes then flip them and crisp the other side. Remove from oven.
Pour the remaining sauce into bowls or mason jars for dunking.