Slice each pepper on one side to create a pocket, remove seeds
Dry each pepper and place a strip of cheese inside, pin close with a toothpick
Lightly flour each pepper and set aside
Heat oil in a large skillet over medium heat, about 3 minutes
Meanwhile, in a stand mixer fitted with a whisk, whisk egg whites on high speed until mixture forms stiff peaks, about 3 minutes
Add egg yolks to whites and continue whisking on high speed until combined, another 20-30 seconds
Holding the pepper by the stem, coat completely with the egg mixture and place immediately into the hot oil
Fry 1-2 minutes per side or until egg coating is golden
Remove the pepper to a paper towel-lined plate and repeat the previous 2 steps for each remaining pepper