Add half of the butter and half of the oil to the pan.
Submerge one side of one of the chicken breasts into the seasoned cassava flour, then shake off excess flour and dip the other side into the flour. Repeat with the other chicken breast.
Brown both sides of both chicken breasts in the oil/butter mixture.
When browned, remove breasts to a paper towel-lined plate.
Use the back of a wooden or plastic spatula to pick up the larger browned flour bits off of the bottom of the pan.
Preheat your oven to 375 degrees F.
Add the remaining oil and butter to the skillet.
Pour the sliced onions, bell peppers and celery strips into the skillet.
Use a wooden spoon to stir the veggies for a few minutes, as they might be over the top of the skillet but will cook down quickly.
Cover the skillet and let the Cajun trinity vegetables caramelize for about 20 to 30 minutes.
When the trinity is about halfway browned, stir the roasted red pepper strips into the mixture.
When the veggies are caramelized, add the grain free chicken broth and beef broth to the skillet, and stir until well-combined.
Place the chicken breasts atop the vegetables, then cover with cheese.
Use heavy pot holders to transfer the skillet to the oven.
Bake for 10 to 20 minutes or until browned and bubbly.
Before removing from the oven, use a digital thermometer to ensure that each chicken breast is at least 165 degrees F before serving.
Let the grain and gluten free Cajun French Onion Chicken stand about 5 minutes before serving.
This recipe makes two very large servings, or four smaller servings. If you're the type of person who only eats and serves half of a chicken breast at a time, you can definitely make this recipe for four people with a salad or side dish.