Beat 1/2 cup of aquafaba (liquid from a can of chickpeas or white beans) with 1/8 teaspoon cream of tartar for 6 minutes. Then slowly add 1 cup of granulated sugar and 1 teaspoon vanilla and beat for 3 more minutes.
Add pecans to the whipped aquafaba and mix well.
Grease a large cookie sheet with cooking spray then pour 1/2 cup melted butter onto the greased pan. Spread the pecan mixture evenly over the melted butter.
Bake at 325° F (162° C) for 40 minutes, taking them every 10 minutes to stir well with a spatula. (Watch them carefully during the last 5 minutes of baking to be sure they don't burn.)
Toss to coat in powdered sugar and cinnamon
While baking, prepare a large gallon ziplock bag with 1 1/2 cups of powdered sugar and 2 teaspoons of cinnamon.
Remove from the oven and allow to cool for about 5 minutes then transfer to a large Ziploc bag with the powdered sugar and cinnamon.
Toss to coat breaking any clumps of nuts apart with your hands. Pour into a candy dish or glass jar for storage. (Allow cooling completely before sealing shut to ensure all excess moisture has escaped.)
Notes
You can line the bottom of the baking tray with parchment paper or a silicone mat, but I find that it's not necessary and I think that they bake better without the liner.
Check on the nuts frequently during the last 5 minutes of baking time. The sugar can start to burn quickly if baked too long.
You can also swap out the pecans for any type of nut that you want.