Preheat the oven to 300 degrees F. Spray a sheet pan with the cooking spray or brush it lightly with oil.
Place the egg white in a large bowl and whisk vigorously for 15 seconds, until light and frothy. Whisk in the brown sugar, vanilla, cinnamon, ginger, chile powder, cloves, 1 teaspoon kosher salt, and 1/2 teaspoon pepper. Add the pecans and mix well, until thoroughly coated. Pour the mixture, including any liquid, onto the prepared pan and spread in a single layer. Bake for 30 minutes, tossing twice with a metal spatula. Each time you toss the pecans, spread them out again in one layer. When they’re done, sprinkle with fleur de sel and allow to cool completely; they will crisp as they cool. Serve at room temperature.