Whisk the egg and heavy cream in a bowl. Combine the breadcrumbs, parmesan, garlic powder, salt, and pepper on a plate. Batter the chicken thighs in the egg mixture, then dredge in the breadcrumbs.
Preheat the air fryer to 400℉. Place the chicken thighs in the air fryer for 15-20 minutes, flipping them halfway through.
Add butter to a small saucepan over medium heat. Once the butter is melted, add in the garlic and lemon zest and simmer for 2-3 minutes. Then stir in the parsley. Once the bubbling subsides, add in crème fraiche and parmesan. Lower the heat to low. Whisk the crème fraiche with the butter until well combined.
Remove the chicken from the air fryer and toss in the sauce immediately or use it as a dipping sauce.
Notes
Press the breadcrumbs into the chicken thighs when dredging with panko. It's important to get full coverage to get the best texture.
Mix a little parmesan in the egg mixture with salt and pepper. This helps layer in the seasoning and flavor into every layer of the chicken.
You may have to air fry in batches to not overcrowd the air fryer.
If you're not serving immediately, then save the sauce to use as a dipping sauce.
The best way to reheat any air fryer meal is to put it right back in the air fryer.