01 -
Preheat oven to 375°F and lightly grease a large casserole dish.
02 -
Peel and cube sweet potatoes into ½-inch pieces. Peel and dice Gala apples into similarly sized pieces. Finely dice the onion.
03 -
Melt butter in a large skillet over medium heat. Add diced onions and sauté 3-4 minutes until translucent. Add sweet potatoes and continue cooking 6-8 minutes until edges soften but centers remain firm.
04 -
Stir in flour and cook 1-2 minutes to remove raw taste. Dissolve chicken bouillon in chicken broth and gradually add to skillet, stirring constantly to avoid lumps. Bring to a simmer.
05 -
Add heavy cream, maple syrup, sage, thyme, salt, and pepper to sauce. Cook 3-4 minutes until thickened. Stir in diced apples to coat evenly.
06 -
Spread shredded turkey evenly in casserole dish. Pour sweet potato, apple, and sauce mixture over turkey, leveling gently with a spatula.
07 -
Sprinkle shredded Gruyère cheese across the top. Bake uncovered in preheated oven for 30–35 minutes until cheese bubbles and turns golden, and sweet potatoes are tender. Tent with foil if browning too fast during final 10 minutes.
08 -
Remove from oven and let rest at least 10 minutes to allow sauce to thicken and slices to hold shape.