First, prepare *AIP Gravy* per recipe [below] (or make it ahead of time, and keep it in the refrigerator until you're ready to assemble this recipe).
Grease a large casserole dish, 9" by 13" or larger.
Add raw chicken thigh pieces, somewhat equally spaced apart. Set aside.
Preheat oven to 375° Fahrenheit.
Heat large skillet over high heat until pan is hot. Add fat. Add onions, optional celery and sea salt. Sauté 8-10 minutes.
Add carrots and dried thyme. Sauté an additional 5 minutes.
Ladle onions and carrots over raw chicken. Add optional (re-intro only) frozen peas.
Add gravy, pouring it evenly over ingredients.
Place casserole dish in preheated oven for 40 minutes, while you make the biscuit dough. [See Biscuit recipe below.]
When biscuit dough is complete, choose to either use a cookie scoop or to cut biscuits into squares. Do not over-mix; follow biscuit guidelines for scooping or cutting.
Remove hot casserole dish from oven. Increase oven temperature to 400°.
Place portioned biscuit batter over the surface of casserole contents. There will be spaces between each biscuit.
Bake in 400° oven 25-30 (additional) minutes, until edges are bubbly, center is very hot and a bit bubbly, and biscuits are tinged with brown and golden.
Remove from heat, and garnish with fresh sage and fresh thyme. (Fresh sage begins to brown when heated, so garnish directly before serving.)