Preheat your oven to 375°F (190°C).
Heat the olive oil in a medium skillet over medium heat and sauté the onion, celery, and carrots until the onions are translucent.
Add the diced chicken breast to the skillet and cook until the exterior is browned and the chicken is nearly cooked through.
Season the mixture with dried thyme, sea salt, and black pepper.
In a small bowl, whisk the arrowroot powder into the cold chicken bone broth until smooth.
Pour the broth mixture into the skillet and stir constantly until the sauce thickens into a glossy gravy.
Stir in the frozen peas and transfer the entire chicken mixture into a small oven-safe baking dish or ramekin.
In a separate small bowl, whisk the egg white and almond flour together until a thick, spreadable paste forms.
Spread the almond flour topping evenly over the chicken filling.
Bake for 15 to 20 minutes until the crust is golden brown and the filling is bubbling around the edges.