If your bread isn't stale, you can cut it up and let it sit out overnight or throw it in a 300 degree oven for 20 minutes.
Preheat your oven to 375 degrees and spray a 4 quart baking dish (16x11) with cooking spray.
In a large saucepan, melt your butter.
Add the onions and celery and cook until soft and translucent.
Add your thyme and sage and season with salt and pepper
Add the chicken stock and bring to a simmer. Remove from the heat
In a separate pan, cook the turkey sausage. One fully cooked, remove from the pan and set aside.
Spray the same pan you cooked the sausage in with cooking spray and cook the mushrooms for about four minutes until softened. At the very end, toss in the kale and let it wilt. Remove from the heat.
In a large bowl, beat the eggs, add the bread and stir to combine. Stir in broth mixture, the kale, mushrooms, sausage and cheese. Pour the whole mixture into your baking dish.
Cover in foil and bake for 30 minutes. Uncover and bake for additional 20 minutes.