To a large cast iron skillet, add the oil & onions. Stir, cooking over medium high heat, just until the onions begin to turn translucent.
2 tbsp olive oil, 1 medium white onion
Stir in the mushrooms and carrots, reducing the heat to medium, cooking and stirring again until the become tender.
1 heaping cup peeled, sliced carrots, 1 cup sliced mushrooms
Stir in the sage, thyme, garlic, and butter. When the butter's melted, stir in the flour until it's adhered to everything and no clumps remain. Let it cook, stirring, for one minute more.
2 tsp minced garlic, 6 fresh sage leaves, 1 1/2 tbsp fresh thyme leaves, 5 tbsp butter, 1/3 cup flour
Add the broth & half & half, a little at a time and stirring constantly, until completely incorporated. Salt & pepper the mixture to taste. Continue cooking until the filling is bubbling and thickened.
1 3/4 cups chicken broth, 1/2 cup half & half, salt & pepper
Fold in the chicken and peas. Remove the skillet from heat.
1 cup frozen peas, thawed, 1 lb chopped rotisserie chicken